SAAC Forum

The Cars => Replicas and Tribute => Topic started by: mlplunkett on August 30, 2021, 11:27:26 AM

Title: Ford's Big Bore Boss 302 block
Post by: mlplunkett on August 30, 2021, 11:27:26 AM
I'm planning the engine build for my 65 GT350R tribute and want to use modern internals (a 302 roller block) while maintaining as much of the original external appearance of the Hipo 289 as practical. I'm thinking about stepping up to the large-bore Boss 302 block from Ford Performance. It would give me the strength of 4-bolt mains and additional interior webbing, roller lifters, extra displacement from the 4.2" bore (in addition to what I would get from 331 stroker components) and with aluminum heads (my only external giveaway) and 10:1 compression I think I'll have upwards of 450 HP. Is anyone aware of anything about these blocks that would prevent me from using all the other Shelby external parts (intake, carb, valve covers, distributor, competition oil pan, etc.) to make this modern block look like a 289?

https://shop.watsonracing.com/BOSS-302-CYLINDER-BLOCK-BIG-BORE-M-6010-A460BB-p/wr-6010-b302bb.htm
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on August 30, 2021, 11:45:29 AM
  Maximum safe bore on those blocks is 4.155 not 4.200. They do not accept a "standard" camshaft because of the "common size" cam bearing machining. 1/2" head bolts ( 351W) head bolts are required as well. The block is significantly heavier than an early 289 block. "I" would ( and have) use a '65-69 block and add Cobra Automotive "HiPo" caps. My 520hp 331 has done this for 20 years without issue. However it is your money.
   Randy
Title: Re: Ford's Big Bore Boss 302 block
Post by: 98SVT - was 06GT on August 30, 2021, 12:32:44 PM
Trust Randy - put that $2,100 somewhere else in the motor. The best rotating parts you can find is the secret to long life at high RPMs. If you're stuck on four main bolts find a good used Boss 302 block. Of course the screw in freeze plugs will be a give away.
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on August 30, 2021, 12:49:59 PM
   "My way " is NOT  "the only way" for sure but it works. The "big bore" is not a great advantage on an "inline" valve head. It is a big deal on a canted valve ( Boss 302) head. Been there , done that. As my friend pbf777 reminded me there IS a "conversion" cam bearing set from Durabond that allows the "standard" cams to be used. "I" would still spend less and use a stroker crank/rods , just me.
   Randy
Title: Re: Ford's Big Bore Boss 302 block
Post by: pbf777 on August 30, 2021, 04:08:46 PM
Is anyone aware of anything about these blocks that would prevent me from using all the other Shelby external parts (intake, carb, valve covers, distributor, competition oil pan, etc.) to make this modern block look like a 289?


      To the best of my memory, the only components not compatible between the O.E.M. production blocks would be the head retention fasteners (the BOSS 302 blocks utilizes fasteners with are about 1/2" longer), a few other fasteners, the cam bearings, and perhaps a little "fitting" of the oil pan.

      Now I'm not sure how much like an O.E.M. 289 block you expect to try and make any of the current production aftermarket blocks to be, but the castings are quite different in external appearances.

      If I were wanting an improved block over the production unit, but that replicated the originals' appearance, the one to find is the older Ford Motorsport M-6010-A4 unit (though these were not intended for the .125+ over-bore); but these are not easily found as they are searched for by many others with the same intent.     ;)

     Scott.
 
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on August 30, 2021, 04:43:28 PM
     My A4 block was safe to 4.100 in a road race type use or 4.125 in a drag race application. I used a 3.5 stroke , Moldex crank for 351ci. The new RDI aluminum block is 4.125 for 374ci. 60 lbs less weight and 23 more inches.
Title: Re: Ford's Big Bore Boss 302 block
Post by: mlplunkett on August 30, 2021, 08:16:28 PM
Thanks guys. That's exactly the kind of input I was looking for. I'll give this some more thought but it sounds like the new block isn't worth the extra $. I wasn't really hung up on the overbore but since they charge the same for the big bore as they do the standard bore I figured it was just free displacement which is free HP. I'll look for a good 302 roller block and go with a stroker and a good set of aluminum heads. I've been told that the Scat and Eagle stroker packages are about the same from a quality standpoint. Any arguments on that front? Seems like I've seen more good press on the Trick Flo heads than others but didn't find a recent comparison test.
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on August 31, 2021, 10:37:23 AM
 Late model hyd roller blocks have a 450 hp "safe limit". Don't waste money on a girdle ( main or valley) as they are worthless. Keep the RPMs down ( 6-6,500) as the blocks also crack because of harmonics. Usually the second main web begins to split . If not abused , it will work fine.
Title: Re: Ford's Big Bore Boss 302 block
Post by: pbf777 on August 31, 2021, 01:47:13 PM
I think I'll have upwards of 450 HP.

Late model hyd roller blocks ................Keep the RPMs down............... If not abused , it will work fine.


      Randy has provided very sage advice, and I agree, but would like to add an emphasis on the "if not abused" part of the statement, as although in instances these blocks have been pushed to this level, and even beyond it for many, but understand for some others, the results,........well.........not so good.      :-\

      Do understand that these O.E.M. blocks were not truly engineered to tolerate such loads, and although as we have practiced in the performance world since its' inception, we push the envelope until realizing failures, that at an unacceptable rate, and then will draw a new line in the sand as to where 'WE' think the components are suitable; but understand that this line is not as definitive as one may often think, and failures, though they should not be necessarily unexpected, are surely unappreciated.     ;)

      Please realize that my perspective is one of a person who is not a real mechanical engineer, and probably suffers from trying to over-build anything I come into contact with; as if the sum of the metal in the structure can be made greater or there is room for one more bolt or just a larger one, then why not mentality.  But ya-know, the guys in battle, in the tank with the most steel armor between them and the munitions being thrust in their direction, usually feel more comfortable and generally will experience better results in survivability   ::)

      Scott.
Title: Re: Ford's Big Bore Boss 302 block
Post by: 98SVT - was 06GT on August 31, 2021, 02:05:57 PM
Please realize that my perspective is one of a person who is not a real mechanical engineer, and probably suffers from trying to over-build anything I come into contact with;

This is sage advice. It's cheaper to over build the first time than have it break and need to do it all over again.
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on August 31, 2021, 05:05:26 PM
    The 5.0 roller block was designed as a "weight savings" block. Bolt holes that used to be "blind" are now "open" ( head bolts , main cap bolts etc.) The main webs were thinned to where they look anorexic. None of this is condusive to reliability with high horsepower. keep that in mind when using them.
Title: Re: Ford's Big Bore Boss 302 block
Post by: mlplunkett on September 01, 2021, 02:37:26 PM
So the early 289 blocks are stronger than a 302 roller block? Any issues with converting the early blocks to roller lifters?
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on September 01, 2021, 03:37:15 PM
   Use "retro fit" tie bar lifters and it's a breeze.
Title: Re: Ford's Big Bore Boss 302 block
Post by: pbf777 on September 01, 2021, 03:48:42 PM
So the early 289 blocks are stronger than a 302 roller block?

     YES!    ;)

   Use "retro fit" tie bar lifters and it's a breeze.

     YES!     :)

     But just costs more!     :o

     Scott.
Title: Re: Ford's Big Bore Boss 302 block
Post by: mlplunkett on September 02, 2021, 03:52:43 PM
Anybody got experience with the aluminum cylinder heads from Shelby Engines?
https://www.shelbyengines.com/collections/all-289-parts/products/shelby-afr-205-cylinder-heads-289?variant=174621982
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on September 02, 2021, 05:17:15 PM
That one is a race head and is of little use unless you intend to use a .700 lift cam. Look at the flow numbers at various lifts.

The AFR 1388 is more practical and flows better then a stock Boss 302 and you only need a .530 ish lift cam.
Title: Re: Ford's Big Bore Boss 302 block
Post by: PrettyMuchAShelbyGuy on September 25, 2021, 11:33:50 PM
What is different from the base 205 AFR head???
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on September 26, 2021, 06:52:07 AM
What is different from the base 205 AFR head???

The 205 is really a race head in the sense that it only out performs the 1388 over .600 lift and is more useful at .700.

The 1388 out flows the stock un-ported Boss 302/351c heads and those number only need a cam in the .500 to .550 lift vicinity. So that makes one more practical for a street/sometimes track car and one only for a full out Bonzi race engine.

Are you going to run an engine that has .700" valve lift and probably something like 8,500 rpm hole shots? Then the 205 is probably what you want but it likely is going to be "just a little sluggish" off of it's 3,500rpm idle?
Title: Re: Ford's Big Bore Boss 302 block
Post by: PrettyMuchAShelbyGuy on September 26, 2021, 01:10:20 PM
So, Iím pretty sure thereís no meaningful difference between the AFR version of that head and the CS version of that head except may be a few hundred dollars and the engraving on the ends. Thatís kind of what I was getting at. You may be better off buying the 195 or 185 versions. Especially if itís going to be streetable.
Title: Re: Ford's Big Bore Boss 302 block
Post by: 98SVT - was 06GT on September 26, 2021, 02:35:41 PM
    The 5.0 roller block was designed as a "weight savings" block. Bolt holes that used to be "blind" are now "open" ( head bolts , main cap bolts etc.) The main webs were thinned to where they look anorexic. None of this is condusive to reliability with high horsepower. keep that in mind when using them.
It was all about the CAFE standards and attitude (and also $ material averaged $1 a pound in the 80s so each one taken out saved $1 per car). Make it lighter for more mileage - as long as it lasts past the warranty period we're good.
We talked to a Ford engineer (in the 80s) who said it averaged a million dollars to take 1 pound out of a car. That spanned the whole gambit from just thinner castings and sheet metal to developing and testing new materials for different jobs. Even thinner glass took more development so it was durable. Thinner sheet metal was made of a different alloy to match the strength of the thicker metal. The crash bars in the doors got an exotic blend with boron so they could be hardened for strength but still be thin and light.
Think about Randy's observations on the block - all new internal molds, new method and sealant for the open bolt holes, engineering tests to see how much can be pulled out of the main webs - for what probably amounted to a less than 5 pound saving.
Ford made the rear windows for GM when they brought out the 3rd gen Camaro. Ford told GM their design would not work but GM insisted on using it. After many broken window warranty claims they had Ford redesign the window using different (more expensive) materials/tempering.
Title: Re: Ford's Big Bore Boss 302 block
Post by: Side-Oilers on September 26, 2021, 06:22:56 PM
A bit off-topic, but responding to 98SVT's post directly above:

Why did Ford make the Camaro windows?  Why help a competitor?

Or was it Ford's glass supplier that did it?  Libby Owens Ford was still around in '82, wasn't it?

Title: Re: Ford's Big Bore Boss 302 block
Post by: 98SVT - was 06GT on September 26, 2021, 06:37:56 PM
A bit off-topic, but responding to 98SVT's post directly above:

Why did Ford make the Camaro windows?  Why help a competitor?

Or was it Ford's glass supplier that did it?  Libby Owens Ford was still around in '82, wasn't it?
Yep Ford owned Libby Owens. Typical outsourcing of parts. Happened a lot more in the late 80s and 90s as manufacturers spun off their parts divisions to try and beat the UAW. I think LOF got sold around 85.
Title: Re: Ford's Big Bore Boss 302 block
Post by: Side-Oilers on September 26, 2021, 06:42:15 PM
We had an early '83 Camaro Z28 H.O. project car at PHR, back in the day.   

The rear glass did crack when the hatchback was slammed one too many times.

We drove it around for about a week like that.  The dealer had no replacement glass, and Chevy PR said to park the car until it could be replaced.

But, why would we want to do that?

It shattered and blew out on a warm night, with the windows down, at high speed.   Quite the surprise.

The next day's hesitant phone call:  "Uh, hello Chevy PR..."
Title: Re: Ford's Big Bore Boss 302 block
Post by: camp upshur on September 26, 2021, 07:02:55 PM
Letís not forget the 1970 429 Cobra Jet D0Of-E OEM carburetor. Which was a Rochester Quadrajet w a Ford part number!
(sorry for thread drift)
Title: Re: Ford's Big Bore Boss 302 block
Post by: 98SVT - was 06GT on September 26, 2021, 07:38:57 PM
Letís not forget the 1970 429 Cobra Jet D0Of-E OEM carburetor. Which was a Rochester Quadrajet w a Ford part number!
(sorry for thread drift)
Or all the Studebakers with Chevy motors, AMC and Chrysler with Delco parts, How many makers used Saginaw steering boxes (or had their own made there)
Title: Re: Ford's Big Bore Boss 302 block
Post by: 5566 on September 26, 2021, 09:26:03 PM
I always thought LOF was owned by Ford too.  Now I don't think so.  Though LOF was a supplier to Ford Motor, it was formed from a merger between Libbey-Owens and the Edward Ford Plate Glass Co. 

https://www.utoledo.edu/library/canaday/HTML_findingaids/MSS-066.html
Title: Re: Ford's Big Bore Boss 302 block
Post by: 98SVT - was 06GT on September 26, 2021, 10:39:30 PM
I always thought LOF was owned by Ford too.  Now I don't think so.  Though LOF was a supplier to Ford Motor, it was formed from a merger between Libbey-Owens and the Edward Ford Plate Glass Co. 
LOF was an old company/supplier who also invented laminated safety glass. I had also thought with that car tie in it was a Ford company. Must have been the old standby Carlite. Which has been sold several times since Ford sold it in the early 2000s.
Title: Re: Ford's Big Bore Boss 302 block
Post by: 5566 on September 27, 2021, 08:05:54 AM
When I was a kid, a buddies dad had a 75 Mark IV. We thought it was cool to stand up through the moon roof and drive around.  I couldn't get over the fact that it had a Fridgidaire AC Compressor.  There was a blank spot where the "GM" logo would usually go.
Title: Re: Ford's Big Bore Boss 302 block
Post by: Cobrask8 on September 27, 2021, 12:23:37 PM
Back to the topic:

I built a very healthy 450-460 HP 331 based on a seasoned 71 302 Block, 10.5 SCAT kit, AFR 185 heads, Howards Cams Cam (Contact me for the spec), plus other good parts. Runs like a bear! Bought all the Heavy Duty AFR head parts, as I have hurt lesser heads. I keep the revs to 6K max, as the cam is from 2500-5500, and is all I need in a 2350 Lb Replica Cobra track car.

Avoid the Motorsports blocks. They crack, and crack everywhere when run hard. When mine exploded (yes, it did), it tried to seize the front crank journal, snapped the crank at #2, and sent the first throw out the front of the block. The remnants of the block was split down the center of the lifter galley, both sides at the bottom of the skirt, and between cam & crank journals. It was almost comical during teardown of the remnants.

Dan
Title: Re: Ford's Big Bore Boss 302 block
Post by: pbf777 on September 27, 2021, 01:27:35 PM
...........snapped the crank at #2, and sent the first throw out the front of the block.


     I don't think in the cases where the crankshaft segmented, one can really criticize the block for being broken.  And we have seen many a good block destroyed in such melees.     ;)

     And, even if the block hadn't broken, chances are the main saddles would be pushed out of position, hence, you still throw the block away!   :o

     Scott.
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on October 08, 2021, 07:44:10 AM
I seem to remember "Ford" explaining the change in the firing order as a fix for the "recently" discovered tendency of even just the little 289 to break cranks.

I don't recall the B2 with it's steel crank having that reputation?


I've got a Scat 347 stroker in my 68 302 block. Looking at the crank, I had concerns. Especially after I got it back from the balancer who turned it into swiss cheese.

I put in a girdle, as if that would help. People run 331's for a reason. I'm thinking all 347's are on borrowed time anyway? Wasn't it Capt.America that said, "we're all living on borrowed time"?
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on October 08, 2021, 11:06:08 AM
   In 52 years of racing them , I have never "broken" a 289 crank nor have I cracked one. Spun bearings? SURE. The Boss 302 cranks ( especially DOZE) have a reputation for cracking in road race use. You have nothing to worry about with a 347 crank. The .150 difference in overall stroke is NOTHING to be concerned about. People act like these cranks create all kinds of stress and strain. I put 50,000 miles on a 347 as a daily driver before I pulled it to inspect and resell. I did go to .040 over because I sold it to a friend. "I" would have simply ball honed and re rung it if I kept it. There are all kinds of "internet isms" out there that are repeated by clueless people. My favorite is "the pin in the oil ring groove will cause excessive oil consumption". Next is "the increase in side loading will wear the pistons out more quickly".  Neither is true.
   Randy
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on October 08, 2021, 01:09:35 PM
   In 52 years of racing them , I have never "broken" a 289 crank nor have I cracked one. Spun bearings? SURE. The Boss 302 cranks ( especially DOZE) have a reputation for cracking in road race use. You have nothing to worry about with a 347 crank. The .150 difference in overall stroke is NOTHING to be concerned about. People act like these cranks create all kinds of stress and strain. I put 50,000 miles on a 347 as a daily driver before I pulled it to inspect and resell. I did go to .040 over because I sold it to a friend. "I" would have simply ball honed and re rung it if I kept it. There are all kinds of "internet isms" out there that are repeated by clueless people. My favorite is "the pin in the oil ring groove will cause excessive oil consumption". Next is "the increase in side loading will wear the pistons out more quickly".  Neither is true.
   Randy

What was causing the issue with the Boss 302 cranks?
Title: Re: Ford's Big Bore Boss 302 block
Post by: CSX2259 on October 09, 2021, 03:21:02 AM
Another trick my engine builder likes to do is use a 351W firing order instead of the 289 firing order. The 289 firing order creates more stress on the engine block.
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on October 09, 2021, 04:25:54 PM
Another trick my engine builder likes to do is use a 351W firing order instead of the 289 firing order. The 289 firing order creates more stress on the engine block.

I never heard that about the block, just late production ('67ish) broken crankshafts. It wasn't about race engines. It was about warranty replacements on production cars.

I never saw that. Neither did I see main bearing failures on 351c's but Ford said yes.

I can see where running the engine out of oil caused the bearing issue but broken crankshafts? How do you do that?

Ford thought they might have an oiling issue with the C's and put 20-50 oil in the B351's.

The 289 crank has to be a casting issue? I never even heard of a racer breaking one. Spun bearings, yes.

The firing order on the 5.0's was changed to the 351w firing order somewhere around 1981. So what took so long if there was an issue? The small block was in production since 1961. It doesn't make sense unless they felt the weaker roller block needed it?

Title: Re: Ford's Big Bore Boss 302 block
Post by: 68countrysedan on October 09, 2021, 08:18:08 PM
It has been suggested that Ford switched from the 1-5 to the 1-3 cylinder firing order because the two consecutive power strokes contributed additional wear on the number 1 main cap bearings.
Title: Re: Ford's Big Bore Boss 302 block
Post by: csxsfm on October 10, 2021, 10:52:46 AM
I lost a few 289 cranks in my road racing days but they were always preceded by rods exiting the block.  LOL
Title: Re: Ford's Big Bore Boss 302 block
Post by: mlplunkett on October 12, 2021, 09:36:25 PM
Let me change the direction of this post a little bit. Sounds like there is agreement that I don't need a racing block to build a 331 stroker that will give me about 450 HP so thanks for that guidance. My new question relates entirely to the appearance of the 302 vs the 289. Since I'm building a GT350R tribute I want the finished engine to look as much like the proper 289 as practical. What problems am I going to have if I start with a 302 block instead of a 289?
Title: Re: Ford's Big Bore Boss 302 block
Post by: mlplunkett on October 13, 2021, 09:22:03 AM
   Use "retro fit" tie bar lifters and it's a breeze.

Randy, Where can I find more info on the lifter package you mention? I'm leaning toward the 289 block to maintain original appearance. Do these lifters require a custom roller cam or are they compatible with standard roller cams? Mickey
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on October 13, 2021, 10:43:22 AM
   Mickey several manufacturers have "tie bar" hydraulic roller lifters, or "retro fit" hydraulic roller lifters. Howard's cams , Morel , Lunati, Crane, etc.
Title: Re: Ford's Big Bore Boss 302 block
Post by: mlplunkett on October 13, 2021, 11:55:30 AM
Thanks Randy. By the way, this is the motor that I'll used that oil cooler on so whenever you get time to ship it, I'm getting closer to needing it.
Title: Re: Ford's Big Bore Boss 302 block
Post by: deathsled on October 13, 2021, 02:16:35 PM
  Maximum safe bore on those blocks is 4.155 not 4.200. They do not accept a "standard" camshaft because of the "common size" cam bearing machining. 1/2" head bolts ( 351W) head bolts are required as well. The block is significantly heavier than an early 289 block. "I" would ( and have) use a '65-69 block and add Cobra Automotive "HiPo" caps. My 520hp 331 has done this for 20 years without issue. However it is your money.
   Randy
That's what you are rocking in your Hertz drag car, Randy?  That's a hell of a lot of HP for such a light car.  Amazing!
Richard E.
Title: Re: Ford's Big Bore Boss 302 block
Post by: gt350hr on October 13, 2021, 03:33:42 PM
    Richard,
        Yes the current engine in the Shelby is a 331 that makes about 525 by the 122 mph at the finish line. I previously had a 351ci Boss 302 that made closer to 600. It rand 10.70's at 127MPH. The engine "on the stand" is a 374CI all aluminum Boss 302 that I "hope" will run in 9.99 "once" . LOL That takes close to 700. Then I might put it "out to pasture".
Title: Re: Ford's Big Bore Boss 302 block
Post by: deathsled on October 13, 2021, 10:23:58 PM
That is pretty damn fast.  Gives modern day cars a serious challenge...
Title: Re: Ford's Big Bore Boss 302 block
Post by: TA Coupe on October 14, 2021, 02:59:10 AM
Link to lifters. You might need a small base circle cam? Randy can tell you.

       Roy
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on October 14, 2021, 06:29:15 AM
You mean everyone isn't running 500+ hp small blocks?  :o
Title: Re: Ford's Big Bore Boss 302 block
Post by: pbf777 on October 14, 2021, 10:58:13 AM
You might need a small base circle cam?     

     Do not get sucked into the "Small-Base-Circle" cam programs!    ;)

     Scott.
Title: Re: Ford's Big Bore Boss 302 block
Post by: pbf777 on October 14, 2021, 11:15:47 AM
You mean everyone isn't running 500+ hp small blocks?  :o

     500?!    :o

     It seems the most common request made by potential customers that enter our shop over the last decade or so follows something like:

          I know it's easy to do, but I don't want to make a thousand horsepower or anything like that, after all I don't want a race engine,.......... ya-know, just your average "mild", "street" engine, making only maybe six hundred or so horse!   ::)

     With the additional follow-up of: 

          Because I (customer) don't really know anything about cars, and don't want something that I would have to work on or fix!      :(

     Scott.

     
Title: Re: Ford's Big Bore Boss 302 block
Post by: shelbydoug on October 14, 2021, 12:47:00 PM
I didn't want to say 600. It would sound like I'm bragging.