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Performance Part 302 engine
#1
Have just recently pick up a 1972 302 long block with 1968 close chambered heads with bored 60 over pistons. Other than that it is a stock build. Thinking about using the current heads because the build is only a month old. Not sure of current compression? I think it may be 9:8:1 based on the current state. Possibly a little over 300 horse with comparable torque.  Would like to add a new intake manifold, four barrel carburetor, headers and a nice performance camshaft and torque converter if needed. that would also go well when I think about changing the heads down the road. With the amount of performance parts available I thought I would look to get some information from the people who have had similar builds done.  What are your thoughts or experiences? I also have a c-4 and a AOD transmission. 

Also looking to update the suspension currently has  and  possibly put some disc brakes on the front end.  Any other suggestion will be appreciated.
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#2
.060 over on a 302 block is too much to trust it to a performance rebuild. Shelby managed to get 271 out of a stock bore 289, but most 302's made no more than 225 from the factory so I doubt you are at 300. I would not try and hot rod that engine. If you want more power start with a block that is bored no more than .030 over.

Between the AOD and the C-4, I would choose the AOD for its overdrive and I would pair it with a 3.89 or 3.70 rear gear. This will allow you to get acceleration and maintain driveability at freeway speeds. Lower gears (higher numerical )are also easier on the engine as the gear multiplication means the engine is under a somewhat lighter load.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
[+] 1 user Likes Jeff73Mach1's post
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#3
Boring and raising compression will do little to raise your horsepower by itself. Your biggest limitation is the stock camshaft. What carburetor and intake are you currently using?

A stock '72 302 made around 140 horsepower at the crank.

You can calculate your compression here
https://www.7173mustangs.com/thread-engi...#pid199290

I agree with Jeff about the .060 bore, too much, and not suitable for a performance engine.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#4
A stock 72 engine was rated at 135 HP but that is net horsepower. In 71 they measured gross horsepower which gives a different and higher number, even though the engines had not really changed in any significant manner.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#5
I do think current horsepower is probably 225 max. Have not decided on the intake, carburator or camshaft yet. Looking to see what thoughts are out there for a good combination. Just looking to build a nice street cruiser with some get up go when needed
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#6
I'm not sure if this will apply directly to your build, but some years back, I read an article in a Mustang magazine, where they took a 2 bbl 289 mustang with an automatic, and put it on a chassis dyno, to get a baseline of horsepower output to the rear wheels. Then, they removed the iron 2 bbl manifold and carb, and replaced it with a stock 4 bbl manifold and Autolite 4100 4 bbl ( two sizes were made, this first one was the smaller 480 cfm unit ). Not suprisingly, horsepower to the rear wheels jumped up. Then, they removed the 480 cfm carb, and put the larger 600 cfm 4100 Autolite carb on. Horsepower figures to the rear wheels DROPPED a bit with the bigger carb! Ford, in their infinite wisdom knew what they were doing, as the 480 cfm carb is what an automatic trans car got from the factory, and the 600 cfm carb was used in four- speed cars, as well as larger engines, like the Hi-Po 289 and the 390.
The point is, if you are running an automatic trans, don't go for a big carb, stay at 500 to 600 cfm with vacuum secondaries or you probably will be throwing away torque and horsepower. Anyway, I wish I had saved that article...I think it was in an old Mustang Monthly magazine.
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#7
(05-07-2018, 01:55 PM)Cresee Wrote: Have just recently pick up a 1972 302 long block with 1968 close chambered heads with bored 60 over pistons.

It is complete junk at .060" unless you live at the north pole.
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#8
Barnette468 is correct. At .060 overbore you will have overheating problems and some spare parts when it is over. Better aftermarket blocks are readily available and not all that expensive. Its like a good foundation on your home.    Ed
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