Author Topic: Ford's Big Bore Boss 302 block  (Read 3316 times)

shelbydoug

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Re: Ford's Big Bore Boss 302 block
« Reply #15 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.
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PrettyMuchAShelbyGuy

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Re: Ford's Big Bore Boss 302 block
« Reply #16 on: September 25, 2021, 11:33:50 PM »
What is different from the base 205 AFR head???
Tom - DFW, Texas

shelbydoug

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Re: Ford's Big Bore Boss 302 block
« Reply #17 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?
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PrettyMuchAShelbyGuy

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Re: Ford's Big Bore Boss 302 block
« Reply #18 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.
Tom - DFW, Texas

98SVT - was 06GT

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Re: Ford's Big Bore Boss 302 block
« Reply #19 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.
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Side-Oilers

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Re: Ford's Big Bore Boss 302 block
« Reply #20 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?

« Last Edit: September 26, 2021, 06:41:37 PM by Side-Oilers »
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98SVT - was 06GT

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Re: Ford's Big Bore Boss 302 block
« Reply #21 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.
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Side-Oilers

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Re: Ford's Big Bore Boss 302 block
« Reply #22 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..."
« Last Edit: September 26, 2021, 06:51:41 PM by Side-Oilers »
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camp upshur

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Re: Ford's Big Bore Boss 302 block
« Reply #23 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)

98SVT - was 06GT

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Re: Ford's Big Bore Boss 302 block
« Reply #24 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)
Previous owner 6S843 - GT350H & 68 GT500 Convert #135.
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5566

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Re: Ford's Big Bore Boss 302 block
« Reply #25 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

98SVT - was 06GT

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Re: Ford's Big Bore Boss 302 block
« Reply #26 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.
Previous owner 6S843 - GT350H & 68 GT500 Convert #135.
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5566

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Re: Ford's Big Bore Boss 302 block
« Reply #27 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.

Cobrask8

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Re: Ford's Big Bore Boss 302 block
« Reply #28 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
« Last Edit: September 27, 2021, 12:25:11 PM by Cobrask8 »

pbf777

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Re: Ford's Big Bore Boss 302 block
« Reply #29 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.
« Last Edit: September 27, 2021, 04:27:14 PM by pbf777 »