My father holds the opinion (he's old school turning 90 in April) that I should get a Cobra Weber intake with the 48 IDA carburetor setup. I, myself, have sufficient concerns that these carburetors are a nightmare to tune and to get running right. They are pretty much a race only piece are they not? I know they look amazing when the hood is opened to reveal them, but what good are they if the car will begin a new life of inactivity in the garage due to constant adjustments. I'm hanging on doggedly to the one four barrel high rise set up and getting it refinished and repaired. If I do go Weber, I need a backup plan if it fails. Am I off base or is there a nugget of truth to the cursed Weber setup? This question was asked by me many moons before but was lost with the crash.
Best regards,
Richard E.
Webers are pretty much a slam dunk. There isn't much if anything that is unknown.
I would caution you if the car was an automatic transmission of if you need to drive the car as everyday transportation in a difficult climate.
Other then that, go for it.
You are not know if they are worth it to you unless you try them.
It seems that you can always get your money out of them if you choose to bail out?
The caution is that they are not going to make your 289 have the power of a 427. It's very difficult to explain the "Weber effect" to a newbie.
Deathsled,
You're off base. There are serveral guys on this forum that run Webers. I am one of them as is Zray, Shelbydoug, Dan Case. They do not go out of tune. They are not difficult to adjust provided your linkage design is sound. There is a fairly steep learning curve in the beginning for a "street" driven Webered car.
In order to run on the street it does require a cam that has a minimum of 112 degrees lobe separation. You might be able to get by with 110 degrees as some claim to do.
Webers originally by design is a isolated runner that requires vacuum unlike a 4V carb that draws air/fuel from a central plenum. Cam profile design needs to be considered.
Webers have a characteristic uniqueness about them and how they "sound and drive"
I've driven my car in the San Francisco Bay Area stop and go commuter traffic. Or the stop and go traffic out of Monterey Car weekend in August (Laguna Seca etc.) with no issues.
Talk to people that actually run Webers not guys that "used to" or "I heard that they...."
Once you get a decent understanding of how it works, you won't want to look at another 14 inch chrome round air cleaner anymore. Just say'n.
Again talk to people that run them, not the BSer's. The only real drawback is that they are expensive (especially for the vintage 48IDA, 48IDA1's, and some early 48IDA4's). And by that i mean just about everything is done in sets of 8. They are infinitely adjustable. A set of 4 48IDA's can flow as much as 2400CFM if need be or less.
As far as looks, these are mine (see pic), vintage 48IDA circa 1964/65 there abouts. Dan Case has an on going data base and the ability to determine the approximate date and period of vintage Webers.
Cheers,
~Earl J
Richard - Although I've only had 2148 for less than 6 months, I'm going to chime in on the Weber question. I was bowled over by the look of the 4 48IDA Webers on top of the Boss 351 in my car the first time I saw it. I was a little concerned that they would be a nightmare to maintain, but I'm just stupid and bold enough to ignore any possible misgivings and went ahead with the purchase. The previous owner, John Barnes, has had them for 40 years on this engine and he assured me they were easier to tune and maintain than a Holley 4BBL. But of course he was going to say that, he was trying to sell me his car!
He included a Haynes manual on Webers, and more importantly, an 8-page guide written by Jim Inglese that he got when he purchased them back in the late 70's. I also spent the time to read everything on Jim's website (http://jiminglese.com/ (http://jiminglese.com/)) and I'm pretty confident that I can at least maintain them and keep them in tune on my ride. I've already had to richen them up a bit to eliminate "popping" at cruising speeds. Super easy fix.
As Earl J mentioned, and as Inglese recommends, you have to run a cam with less overlap than with a plenum manifold and you have to choose the correct choke size for your application. Webers don't have chokes like traditional carburetors. Weber chokes are actually sleeves that are inserted in the carb throat to adjust the CFM flow. It's important to size them for your application. 48IDA's can be used on everything from a 289 to a 427 by choosing the correct choke. And by the way, I was concerned about cold starts with no choke but that's not an issue. Pump the gas once and it fires right up.
If you choose to go this route, make sure that you have a well-designed linkage and fuel pressure regulator as well. If I was starting from scratch I would rely on the expertise of someone who has experience setting them up and running them to guide me through the process (or just buy a turn-key setup) so you can maximize the pleasure you'll get out of them.
They are magnets at car shows. Pop the hood and watch the crowd gather! At local shows most people have no idea what they are. At serious shows many do and they love to look! Keep lots of towels handy to wipe the drool off your fenders ;)
Performance wise, I couldn't be happier! The mid-range torque and the howl they make when you open them up is nothing less than intoxicating. My B351 has 11.5:1 compression ratio so I run a blend of 110 purple race gas and 91 non-ethanol to make sure there's no detonation, but depending on your CR you can run lower octane levels if your engine is happy with it. Although I like to open it up frequently, I don't "need" to. Once the engine is warmed up you can drive it very conservatively for just cruising around if that's what you want to do. My car has a Richmond 5-speed stick and I live in Florida so I'm not dealing with cold weather driving. I am not sure how they work with an automatic.
One potential downside is the lack of a traditional air filter. I've run mine with nothing on them, but currently have wire mesh screens on them to keep out leaves and small animals. The hood clearance on my 68 GT350 doesn't allow for a large plenum air box or stack-type filters and I've been warned not to use the foam filters as they will eventually deteriorate and get sucked into the engine. Also, they can become fuel soaked and cause a fire (you do have a fire extinguisher on board, right?). So driving in dusty conditions can result in some amount of trash getting sucked into your engine. I try not to drive mine on windy days when the sand gets kicked up, but every once in a while I have to drive by a lawn maintenance guy using his 35HP leaf blower to blast debris into the road so someone's lawn looks prettier. Not good for my engine or paint.
I'm still very new to this and you can take my comments with a grain of salt. I would defer to the folks who have years of experience with these setups, but I wanted to give you my take as a newbie Weber user. Best of luck with whatever you decide!
Here's a link to what I think is one of the better guides to understanding, setting up, and tuning Webers. (I hope this works). It's a long read but really good. There are other books and Jim Inglese has a very good installation guide as well. Also don't confuse Inglese (by CompCams) and Jim Inglese. (Long story, but explained on Jim's website).
http://www.timsroadster.com/html/tuning_webers.html
Cheers,
~Earl J
I did forget to mention that my car has a 12 volt electric vacuum pump for the power brake booster. Weber setups don't create a lot of vacuum so that is a consideration as well.
Kevin
I have a weber set up on 6S1904. Jim C. put them on in 1990 and they have been on ever since. The car has been driven and they are a blast to have. In the entire time I have had them on, they have only had to be tuned once. I live in WI and the up and down weather does not effect them at all. I couldn't be happier and I have a set waiting to go on CSX2122 when I pull the motor. I couldn't see 1904 with anything but- A must have. I also second Dan Case if you have weber questions on originality etc. He has tons of documentation if you want to make sure you are period correct.
Jeff-
Eye candy for sure!! 8)
Gentlemen excellent information provided and thank you. 843 is a 4 speed Ford Toploader with richmond gears came out of Peter Klutt's racing Hertz. Naturally car was automatic originally and I'll put an automatic in when my knees go but that gives me a good 30 years more of rowing the gears. I presume a modified Monte Carlo bar is used. It's not rocket science. It's carburetor science!
Best regards,
Richard E.
On the cam, you can run anything that you want to.
The appearance of the so called "Weber Cam" was something that Jim Inglese worked on with CompCams I believe?
All it does is reduce the amount of overlap in the cam timing in order to reduce the "blowback" out of the velocity stacks. It also cuts a good deal of power out of the engine. Around 30 hp I would say?
It came about because lots of people wanted to run air cleaners on the carbs, not open stacks or just screens.
If you do that with a camshaft with more than about 28 to 30 degrees of overlap, the blowback will soak the air filter elements with atomized fuel. That's the overlap a Weber cam has, about 28 degrees. That would be a stock Ford 351 Cleveland cam.
With the air filter elements wet with fuel when you go to restart the car, they WILL catch fire. If you are going to run without air cleaners and just stacks, you don't need the Weber cam.
When the carbs were raced on the Cobras there was no such thing as a "Weber cam". They ran what they would normally run in a competition car. No air filters.
Besides catching fire, the air filters will take about 80-100hp out of the engine which is about what they were adding to it in the first place.
Likewise the GT40's ran Webers with just open velocity stacks.
One of the issues with them on "Shelbys", not so much with the Cobras, is that you can't run the length of stack that overcomes much of the blowback, and tunes the torque more precisely.
If you notice KJspeeds stacks, they are all shortened as are the auxiliary venturies. The reason for that is on the 68 Shelby, there isn't enough hood clearance on the front two stacks so they need to be shortened.
I had that exact setup on my 68 GT350. Boss 351 and all. I think that's where John first saw it? Only my front two stacks were shortened. The rest were stock 3-1/2" height. That was 1978-79.
I have them on my Pantera now but that enables the carbs to run the full 5" tall stacks. If you look at vintage pictures of the Group 4 factory race Panteras, all of the stacks have been extended to about 5" tall.
In addition to changing the torque characteristics of the carbs, it also keeps the "vapor cloud" within the stack, or most of it anyway.
How I would paraphrase what everyone else has said here is that the carbs are very streetable, actually creating a true street/track car, and that they are just a bit of a learning curve because they are so different from what most have experienced.
I think they are worth it. I've taken them off twice under fits of rage, but have always come back to them.
It's kinda like being married to an Italian movie star. The rewards are great and you are going to be in for a few very, very interesting side journeys? Look out for the ones that throw things at you like frying pans and such. They take longer to recover from. Learn to duck. ;)
shelbydoug,
There is some truth in what you're saying about running "any" cam on the race track BUT on the street where the engine sees real world slower speeds, lower RPM's, stop and go traffic. The "Any Cam" isn't going to cut it. Sorry to contradict you. That's why the cam from the Inglese/CompCams people offer and the need to be selective about cams. I think it's the same reason the people that "Used to" attempt to run them gave up.
Running Webers on the street there is a significant amount of reversion ('blowback" as you call it) of air/fuel mixture running with the wrong cam (intake valve opening before exhaust cycle is complete). A cam designed for Webers to run on the street NEEDS vacuum to run lower RPM's. You get that with more lobe separation.
There are other factors too i.e. timing, gear ratio, compression ratio etc. One of the most important details in the tuning process is the float settings need to be precise and your linkage needs to be of a good design. (I built my own).
Webers for the race track, do what you want or need. You're running the engine in the upper RPM range. As much as I would love to run a "LeMans Cam" with Webers on the street. It just won't work well, unlike with a 4V. Just my 2 cents.
Cheers,
~Earl J
I suppose to further the questioning Richard (OP) might ask: I notice there are two types of intake manifolds for the sbf, for Webers. One
has two water exits and the other looks like normal one (with thermostat housing). Any advantage / disadvantage to either?
Quote from: SFM5S000 on March 14, 2018, 10:49:16 AM
shelbydoug,
There is some truth in what you're saying about running "any" cam on the race track BUT on the street where the engine sees real world slower speeds, lower RPM's, stop and go traffic. The "Any Cam" isn't going to cut it. Sorry to contradict you. That's why the cam from the Inglese/CompCams people offer and the need to be selective about cams. I think it's the same reason the people that "Used to" attempt to run them gave up.
Running Webers on the street there is a significant amount of reversion ('blowback" as you call it) of air/fuel mixture running with the wrong cam (intake valve opening before exhaust cycle is complete). A cam designed for Webers to run on the street NEEDS vacuum to run lower RPM's. You get that with more lobe separation.
There are other factors too i.e. timing, gear ratio, compression ratio etc. One of the most important details in the tuning process is the float settings need to be precise and your linkage needs to be of a good design. (I built my own).
Webers for the race track, do what you want or need. You're running the engine in the upper RPM range. As much as I would love to run a "LeMans Cam" with Webers on the street. It just won't work well, unlike with a 4V. Just my 2 cents.
Cheers,
~Earl J
I installed my first system in 1978. There was no such cam. I've been running them ever since in various vehicles.
The Weber 48 IDA "eight stack" is not and was never intended to be a "street induction system".
It is a system that can be used on the street.
Lots of what makes them streetable or unstreetable is really taste or personal preference.
I don't disagree with you necessarily, but what I am saying is a special cam for them is in itself a compromise and to a great degree takes out of the system what you put it on the engine to gain.
This is part of the "indecisiveness" of what makes the setup questionable in the minds of the uninitiated.
Just running open stacks on carbs on the street is risky to say the least.
Until you get to around 80 degrees of overlap, you are going to get 12-14 inches of vacuum no matter what cam you use and no matter how you plumb them the system won't provide the VOLUME of vacuum that you need to operate power brakes (as per the vacuum pump in KJSpeed's '68).
I have a vacuum pump in my Pantera also.
Other then that, the issue is with blowback with air cleaners getting soaked with fuel, besides a very heavy idle.
I'm ok with someone using a Weber cam. I'm just saying it isn't necessary. Reasonable people can disagree. That's fine.
This is like disagreeing over Lasagna. I like it with some sausage mixed in and a crunchy top.
Some like Merlot with it. I like Pinot Grigio, better yet Bud Light (tastes great - less filling). Call me crazy?
Lasagna
Now that's a topic
Red lasagna better than white.
Quote from: Bigfoot on March 14, 2018, 02:08:38 PM
Red lasagna better than white.
(pssst!...Bud Light!) ;)
shelbydoug,
You're right when Cobras and GT40's "Raced" back in the day, they did run without filters. They "raced" with racing cam profiles. That same cam profile does not work well on the street then or now.
I think I can safely say, most people who run Weber's today do it for the esthetic reasons because of their potential and lore of being the ultimate carburetion system of the day which it was.
There's something about the 8 velocity stacks and the symmetry of the carburetor bodies, fuel line and nuts that are visually attractive from a mechanical point of view, heck Ferrari's had Weber's.
To me Weber's look best without screens or filters ( I actually drive with screens) standing still. And yes you are right again people that ran with a form of filter system got vapor fume soaked and had a propensity to catch fire when re-starting, and in doing so very easily turning the car into a Car-B-Que, you best have or carry a fire extinguisher.
Funny shelbydoug I'm not really a fan of Lasagna, I'll eat it though but my preference is more for a meaty Bolognese style spaghetti sauce over a Rotini pasta because with spaghetti noodles you end up wearing sauce on your shirt and I've never found it fashionable to tuck the dinner napkin into the collar of my shirt. White wine (Pinot Grigio) with Lasagna? Seriously? Don't get me going on wine, remember I'm from NorCal (Napa, Sonoma, Alexandria, Tri Valley, Coastal, Paso Robles etc. ) NorCal does red wine, and white too.
Back to Weber Manifolds
~E
Quote from: gjz30075 on March 14, 2018, 11:27:40 AM
I suppose to further the questioning Richard (OP) might ask: I notice there are two types of intake manifolds for the sbf, for Webers. One
has two water exits and the other looks like normal one (with thermostat housing). Any advantage / disadvantage to either?
Greg,
You're opening a can of worms by asking that. Not only are there different (Modern version) thermostat/ (original configuration) no thermostat with "Y" water neck. There is also orientation of carburetors butterflies and which way they swing open noted by the way the fuel line passes to the outside vs fuel line up the middle. As well as the "Cobra" castings from OECO (Offenhauser Engineering Co) and the FoMoCo E&F (Engineering and Foundry) both very different in appearance and spacing. Then the reproduction pieces from Blue Thunder and whomever else over the years.
I'll let others elaborate on the variations of manifolds.
I own examples of both OECO and E&F.
Cheers,
~Earl J
Jim Cowles ran for 30 some odd years on the street with CSX2138(?). Ask him what he thinks.
Lots of comp cars ran with just the stock 289hp camshaft.
I would say that if you are going to take the "cam" out of it, you might as well cut down the size of the chokes to 30 to 32mm? Those would be a street setting.
You see, it's not just the cam that is involved in this. It is the entire induction system. That includes the flow of the heads, the flow of the exhaust manifolds, the flow of the carbs.
Heck, you might even be able to put a cam and mufflers on this thing so you can cruise around town and play a nice stereo with lots of violins and children's choirs and be able to have a conversation with your passenger without yelling? It could be a very relaxing experience I suppose?
Yes, Pinot Grigio. Comon'. Walk on the wild side. If you wanna' talk the talk, you gotta' walk the walk, otherwise just make a coffee table out of them. They are industrial art. You can sit around with your friends drinking a Merlot, put the a/c on high and get plastered playing with the throttle. ;)
between 2122 and 2138 it was about 25 years. I ran no screens and 42 chokes. dyno shows when you run screens it loses about 40 HP if I recall. On a small block thats a ton. I didnt want any of the chebby big blocks to get the best of me
Quote from: acman63 on March 14, 2018, 04:31:45 PM
between 2122 and 2138 it was about 25 years. I ran no screens and 42 chokes. dyno shows when you run screens it loses about 40 HP if I recall. On a small block thats a ton. I didnt want any of the chebby big blocks to get the best of me
What cam Jim?
What factors enter into the equation to determine proper choke on a 48IDA?
Closing down the chokes would have the same effect as putting a smaller Holley on an engine.
For instance if you took the 715 off of your '65 and put a 1848 on it. You would get an immediate torque response to it at the expense of loosing upper rpm.
The Cobras ran 42mm "chokes" as Weber refers to them and in these carbs they are changeable.
A new IDA now, and for a long time now would come with a 37mm choke.
So what you really are seeing is the large "tuning" capability. That includes the engine displacement as part of the tuning.
Most are not that used to this kind of flexibility.
Probably a street small block is better off with a 37mm choke.
It isn't just the size of the choke that matters, the bore of the carb, i.e., in this case 48mm is significant also.
A 351 really needs a 51mm and a 427 a 58mm.
There are at least three different Weber manifolds and multiple variants of each for the 289 Ford application....
1) Early Cobra opposed
2) Later Cobra parallel
3) Ford produced parallel, GT40 application
None of which have a built in thermostat housing.
Quote from: CSX2259 on March 14, 2018, 09:14:39 PM
There are at least three different Weber manifolds and multiple variants of each for the 289 Ford application....
1) Early Cobra opposed
2) Later Cobra parallel
3) Ford produced parallel, GT40 application
None of which have a built in thermostat housing.
That Cobra in your avatar is pretty damned hot!
deathsled,
Thank you, it has Weber's too!
Quote from: shelbydoug on March 14, 2018, 05:02:40 PM
Quote from: acman63 on March 14, 2018, 04:31:45 PM
between 2122 and 2138 it was about 25 years. I ran no screens and 42 chokes. dyno shows when you run screens it loses about 40 HP if I recall. On a small block thats a ton. I didnt want any of the chebby big blocks to get the best of me
What cam Jim?
No idea. I never cracked the engine open. Im guessing it was similar to Lemans grind. same cam that Murray ran at road atlanta/ could rev this as high as the gasoline would let me. nothing like webers for instant response
Jim,
Did 2138 have 48 IDMs on it?
if you don't have a good deal of experience with carburetors in general , I'l suggest ponying up the extra $$ and have Jim Inglese provide and set up the Webers for you. His set-up's are always right in the ballbark, if not spot on for any given application. more than likely you will not have to do much in the way of tuning besides a very basic synchronization when you first put them on. After that, just enjoy them
Z.
https://www.jiminglese.com/
Quote from: zray on March 14, 2018, 11:57:01 PM
if you don't have a good deal of experience with carburetors in general , I'l suggest ponying up the extra $$ and have Jim Inglese provide and set up the Webers for you. His set-up sare always right in the ballbark, if not stop on for an y given application. more than likely you will not have to do much in the way of tuning besides a very basic synchronization when you first put them on. After that, just enjoy them
Z.
https://www.jiminglese.com/
Excellent advice. +1.
++1
addendum:
I experimented with cams a little with my Weber set up. I had a special cam made up with a little more lobe separation angle than the stock HiPo cam has. It was different in the lift also.
I came away thinking I should've stuck with the stock HiPo cam. The 289 HiPo doesn't have an abundance of low rpm torque anyway. When you start putting custom cams in it, the usual result is the high rpm power is increased , YEA !!! But the flip side is the low rpm torque and horsepower is diminished. BOO !!!
That won't matter if you are going to be on the track all the time, but it's a real buzzkill for street driving. There no free lunch when it comes to cam design, what bonus you get on the top end, you will have an equal negative effect on the low end. Unless you modify the motor to have variable cam timing. And I haven't seen a huge aftermarket need for that yet.
Think hard and long before putting in a whiz-bang cam that gives you a lot of top end. You will hate it when driving in the real world.
Z
Thanks for your input zray. I shall consider it.
Richard E.
I have 48 IDA's (fourth casting release version) on COBRA Intake (fuel line on the outsides) setup with linkage etc., that was bought new from Inglese in the '80's. I did get some info from Dan Case (Thanks Dan) on these and they could be available.
Very seductive and difficult to resist. 8)
Do Webers "like" higher or lower compression engines? Part 2 of the question is what constitutes hign and low compression as it relates to Webers?
The only thing that bothers me with running Webers is the lack of a filter. Sucking crap in the engine is troublesome and risky IMO.
For cars requiring vacuum for things like brakes, will plumbing the cobra weber intake provide enough vacuum for the brakes?
If anyone has an early "opposed" original intake I am in need of one and will pay up for it if you are willing to part with it knowing it will end up on 2122.
Thanks-
Jeff
Quote from: mygt350 on March 16, 2018, 08:50:06 AM
Do Webers "like" higher or lower compression engines? Part 2 of the question is what constitutes hign and low compression as it relates to Webers?
The higher the compression, the "crisper" they run. Don't go under about 9.5:1 with them.
Running with any open carbs is a risk. Some sort of a screen on the street is really minimal but if you have the room you can do more with the screens. The greater the surface area the less of a flow drop you will have BUT it isn't a direct proportion. Consult with a Professional Engineer for flow characteristics calculations.
There are those who think they can run power brakes off of the vacuum of one cylinder. I disagree.
There are many vacuum reservoir/manifold designs around but I find that it's the nature of an independent runner manifold more then the carbs not to be able to supply the volume of vacuum necessary and after years of trying to discover a solution I finally gave up and went to a Compcams vacuum pump.
It's a little annoying because it's a mini-compressor and sounds like it but with the noise of the headers, solid lifter cam, etc., the sound just gets lost in there anyway.
For those reading this that are going to disagree with the comment about "lack of volume of vacuum" because they are running electronic fuel injection and they do get enough vacuum, carbs and fi set ups are not equal in this respect.
Quote from: Greg on March 16, 2018, 09:21:16 AM
The only thing that bothers me with running Webers is the lack of a filter. Sucking crap in the engine is troublesome and risky IMO.
Not sure what the performance help/hurt is on these but K&N does make a filter unit for these, others will know better. It doesn't have filter material above where reversion flame and fuel can burn/soak it has metal. Does take-away some of the wow factor.
Quote from: mygt350 on March 16, 2018, 08:50:06 AM
Do Webers "like" higher or lower compression engines? Part 2 of the question is what constitutes hign and low compression as it relates to Webers?
The K code engine I had the. Webers on had a measured CR of 10.0:1. Detuning a car by lowering the CR would be shooting yourself the foot. The Webers do more than just provide eye candy. Properly set up you will see improvements in torque and horsepower. Lowering the CR will only serve to minimize or negate those gains?
The following chart may interest you, it was copied from the 1965 Ford High Performance Catalog (for ordering thru Ford dealers)
Quote from the catalog:
"Horsepower Figures were obtained from actual dynometer test programs by Shelby-American Inc."
Stock 289 w/ one 4V 232 @ 5,500 rpm (A code I'm supposing)
289 Performance 4v kit 286 @ 6,500 rpm (I think the carb is a Holley 715 w/ the Cobra Hi Rise manifold.
289 w/ two 4V carbs kit. 276 @ 6,000 rpm
289 w/ three 2V carbs kit 314 @. 6,500 rpm
289 w/ four 2V carbs (Weber 48 IDA carbs) kit 345 @ 6,500 rpm
Quote from: Greg on March 16, 2018, 09:21:16 AM
The only thing that bothers me with running Webers is the lack of a filter. Sucking crap in the engine is troublesome and risky IMO.
I ran my 48 IDA set for 2 1/2 years, and over 20,000 miles. Most of time I used some screens that Jim Inglese sells. They are not just the just plain mesh, they filter down to 10 microns or some ridiculously small number. I tried running without them on occasion and really couldn't tell a difference in performance. I was using two AEM a/f meters, and their readings didn't change whether the screens were in or not. So I'd question Jim and try those same filters. I had occasion to drop the oil pan to fix a leak, and also changed a head gasket.. After 20,000+ miles, no measurable wear. I took that car a few long-ish trips of 1,000 miles round trip. It performed great on the highway with the Webers. The torque improvement made passing slower cars a real treat.
Quote from: mygt350 on March 16, 2018, 09:23:16 AM
For cars requiring vacuum for things like brakes, will plumbing the cobra weber intake provide enough vacuum for the brakes?
You can either get an electric vacuum, or use a Weber manifold that has a sealed off plenum, in which all 8 cylinders are connected to via a small drilled hole in the runner. I used that type of manifold so I could run a PCV valve. I wasn't too keen on all the cylinders having a connective plenum, as it seemed that was negating the benefits of a IR manifold. So I did experiment with plugging up the connecting holes and shutting off the plenum, and just having an open breather w/o a PCV valve. I couldn't really feel any performance difference, and the a/f meters displays were unchanged one way or the other, I so unplugged the holes and went back to using the plenum acting as a vacuum source for the PCV system.
I don't think you can get a plenum manifold in the dual waterneck style, not sure about that.
Z
PS. BTW, I had a permanently installed vacuum gauge, and had 10" vacuum with my Webers.
If those filter tops and bottoms were cast like Valve covers they would look right in place.
Miniature oval air cleaners but with no script. Shot peened billet pieces may look close, then any machine shop could make them.
With a stock 65 or 66 hood I think you would need to use shorter (not optimal) stacks to use any air filter.
I barely had enough room above the rear stacks, and eventually went to a set of Ron Morris 1/2" lowering engine mounts.
Z
Have seen a Weber manifold with stainless hard lines connected to a fitting drilled in each runner just below each stack. All eight lines ran to a block with a single vacuum port. Would that be adequate for power brakes? Where would PCV be plumbed to?
Quote from: mygt350 on March 16, 2018, 10:58:53 AM
Have seen a Weber manifold with stainless hard lines connected to a fitting drilled in each runner just below each stack. All eight lines ran to a block with a single vacuum port. Would that be adequate for power brakes? Where would PCV be plumbed to?
I've seen those too.. Too many connections to have potential vacuum leaks, and too much complexity for my tastes. I don't think you are going to have enough combined vacuum to operate both power brakes and have a PCV system with a decent vacuum. I only had 10" of vacuum, and that was on a relatively fresh overhaul.
If you have to have power brakes, I think you are going to need some type vacuum pump, either electric or engine driven.
Z
Quote from: mygt350 on March 16, 2018, 10:58:53 AM
Have seen a Weber manifold with stainless hard lines connected to a fitting drilled in each runner just below each stack. All eight lines ran to a block with a single vacuum port. Would that be adequate for power brakes? Where would PCV be plumbed to?
for a visual reference (there may be others) ...
Look like those are hose barbs. One I saw had stainless hard lines to each port. Was really interesting to see how each tube was bent to not collide with any of the others. Lots of connections that could cause a vacuum leak though.
Quote from: mygt350 on March 16, 2018, 10:58:53 AM
Have seen a Weber manifold with stainless hard lines connected to a fitting drilled in each runner just below each stack. All eight lines ran to a block with a single vacuum port. Would that be adequate for power brakes? Where would PCV be plumbed to?
You mean like this? That's my set up initially. It's a little different now on the car.
Now this is how it is plumbed for my Pantera and the car has different space considerations for things like the vacuum manifold, i.e., where things are located and how is because of the access to them. On a "Mustang" where you would put things and even the way the linkage is done varies. The Pantera has very specific requirements to make things work.
In my case, there isn't enough volume of vacuum to operated the Pantera power brake booster. It is possible, even likely that different power booster require different volumes? That I never played with.
When the Webers were in my Shelby I ran manual brakes with the big 1-1/4" bore master cylinder.
On the air filters, it doesn't matter where the element is, it will get soaked with atomized fuel.
There are other engine configurations that do not create a push back through the intake ports.
6 cylinders do not, 4 cylinders do not. I don't know about 12 cylinder engines like Ferarri's. So what the issue is of blow back is the normal camshaft design for an 8 cylinder engine.
You can run the 46IDA-3 on the Porsche 6 cylinder, the Corvair that has been converted to the Porsche design, use two 48IDA's on a 4cylinder VW dune buggy. NONE of them have an "overlapping cam design" so none of them pressurize the intake port causing the blow back.
The simplest way to fix this on any V8 is to go to the Weber look alike fuel injection throttle bodies. Then since there is no atomized fuel in suspension, there is no blowback AND you can run any kind of an air cleaner that you want.
The difference is that the carbs are a $3,500 swap. The FI is about a $5,500 swap because of the computer and other electronics needed.
My information tends to agree with what Z is saying but I have only run them on my 351's. The horsepower loss over running open stacks vs. air filters is 80 to 100hp LOST with air cleaners. That's about what you gain by adding the carbs to begin with.
IF all things were exactly equal, you can clearly show this on an engine dyno. A single Holley 4179, 750cfm, double pumper carb will clearly show around 80 hp less then the Webers on the exact same engine. But you get into variables as well.
As Jim Cowles just posted above, even the screens show about a 40hp loss over open stacks, but you need them to keep the squirrels from getting sucked in.
For instance this particular engine makes another 80 hp with 2" primary tube, 180 degree headers over the 1-3/4" dyno headers. In a Pantera you can fit those headers. In a "Mustang", you can't.
So just because of the different chassis the same engine is in you can use the taller 5" velocity stacks and the bigger headers. That's around 100 hp more then you can get with the same engine in the "Mustang" because of the limitations.
So, all things aren't equal.
OH, and just so the Cobra guys don't feel left out, "it was said" (not by me and I don't know exactly who) that the GT40's with virtually the same engine as the race Cobras, made 100 hp more because of the headers (bundle of snakes).
I don't know where my pictures are of the Boss 351 with the Webers in my 68 GT350 are right now. Those are circa 1978-9.
That set up was a little different BUT you can still NOW see the charred marks on the bottom of the hood from the Webers from start up. Particularly the front two stacks.
I remember Kopec hanging around until dark for me to start the car in the dark so he could take pictures of the flames coming out of the carbs that you don't see in the light. Leave it to him. I wonder if he can find those?
I had a nice video of an engine on the dyno. An iron head 357 with Webers making 600 hp @ 6500, 500 lb-ft @ 5,000, and it showed the vapor hovering like clouds just over the top of the 3-1/2" stacks that were on the carbs. That was as clear as it gets about the blowback. Put a 5" stack on them, the vapor stays in the stack.
Put a "Weber cam" in that engine, deduct 80hp.
Here is a pic of the Cobra Weber intake with hard vacuum lines to each port.
The post by JD identifies 4 carbs. The 4th version with the tabs has date code of L8 which indicates Nov 78. Am looking at a 48IDA4 with the tabs and it has a "1F' date code. Does this indicate Jun 71? Were date codes always alpha/num, num/alpha or both?
Quote from: mygt350 on March 16, 2018, 01:02:34 PM
Here is a pic of the Cobra Weber intake with hard vacuum lines to each port.
On the Shelby you can do that. On the Pantera, the center valley is taken up by the linkage. My vacuum pick ups are on the exterior and go to a long vacuum manifold tucked in behind the header heat shield.
Quote from: mygt350 on March 16, 2018, 01:12:28 PM
The post by JD identifies 4 carbs. The 4th version with the tabs has date code of L8 which indicates Nov 78. Am looking at a 48IDA4 with the tabs and it has a "1F' date code. Does this indicate Jun 71? Were date codes always alpha/num, num/alpha or both?
You need to ask Dan Case. He's the expert on the date codes. To me the only significance is someone trying to get super premium money for what they call an "original" set obviously made in the '70s but supposedly original to the mid '60s.
Functionally they all work the same.
Here are the tall velocity stacks.
Here's the Compcams vacuum pump.