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Old 08-25-2004, 09:57 AM
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Thumbs up build a 302 or 327

I have a 66 CE 327 block with 186 heads and a 57' 283 crank.

Question: Is the 327 with 186 heads to high of compression today to run on pump gas?

I am wondering wether to keep the 327 and rebuild or use the 283 crank to make a 302? Going in a 1960 2wd pickup? Will the 302 smaller displacement help with compression?


I also have my choice of 200R4,th400 or the sm420 4 speed (currently using 4 speed). (too many parts trucks for combos) curently with 307s rear end.

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Old 08-25-2004, 11:05 AM
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The compression depends on what pistons you match with the head your using. You could have a 327 with flat tops and the compression might be 9 to 1 with "X" head. You could build the 302 with the pistons that GM put in the 302 and the compression would be much higher than the 327 with flat tops and the same head.

With "X" head and flat top pistons in each engine, the compression ratio would be the same.

The 186 head with flat top pistons is perfectly suited to street use.

If you are replacing the 4 speed with either of the auto trans you mentioned, my choice would be the 327. The 302 is a high reving engine that benefits from a standard trans and a tall rear axle ratio. The 302 has less lo end grunt than the 327 has.

Vince
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Old 08-25-2004, 11:18 AM
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I would build the 327, you need the extra engine size in a P/U. The 186 heads would put your compression ratio at borderline if you use standard height pistons and the block is fairly close to spec. If you use rebuilders pistons, the compression ratio will be a bit less.

186 heads are not usable with modern gasoline. Most of these heads will cost more to rebuild than the rest of the engine. I would go with some post 76 heads with larger chambers and hard seats, or if the budget allows, get the best of both worlds with some good aftermkt heads.

I had a 60 shortbed stepside Chevy with the double hump dash. 350 with a 350turbo. Today with gas at $2.00/gal, I would definatly go with the overdrive trans.
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