compression question

well guys, about to purchase the heads for my engine.
The pistions i have are stock forged 4.00 in 4 v relief flat tops.
I want to hit around the 9.5:1 compression, something very streetable

what cc heads should i go for? 58cc, or 60cc?

thanks

 

58cc would be my guess because I am using 61cc chambers on a 351W with flat top 4 reliefs and get 10.1:1 compression

 

First of all, you have to figure which flat topped 4 valve relief pistons you have. They're not all the same. The pin heights vary from 1.585 to 1.620.(for 289/302 pistons) That .040 difference will change the ratio by up to a full point. It's like adding an extra head gasket into the mix. The volume of that .040 is about 9 ccs. Which is a huge factor in a 302. Do your homework before buying heads.

 

well i just picked up a set of trickflow 170cc heads 61cc chamber came with bolts pushrods and rocker arms for a grand shipped. they are lightly used
now i can figure out what compression ratio and if need be shave the heads a tad to hit 9.5:1 to 10:1 im shooting for.
ive had a couple sets of trickflow heads on my impala and loved them. first set on a ford, should be interesting.

 

Sweet i picked up the same set also a while back when they were on sale!

I've been looking at the flow numbers and the trick flow seams like the second best set of heads for a mild build, right before AFR's

but those are a bit too pricey for my book

 

well picked up a set of doug's headers off of ebay should be a good combo.

 

The D668's? those are nice!

how much did you get them for?

 

i got the thy-268d chrome headers for $125 plus shipping..

 

ahh those are dougs thorleys!

theres two header companies

dougs headers



and dough thorley headers



i got confused.

 

shock tower modification

well my first attempt at metal fabrication. could be better i figured when i get the car repainted they can smooth them out some more but there in and no interference issues. this will give me some space to get around the engine
thanks guys for the idea.

 

Looks good to me. Nice job. You should see the welds my bro-in-law left me to smooth over :16suspect

 

well quick compression question.. i have the trickflow heads that are 170 61cc chamber.

i have .013 for piston to top of the block. .047 for the gasket height. 4 in bore and 3 in stroke. math is coming out at 8.8 on the ratio. what is my best bet on raising the compression. i was thinking of milling down the heads .050 which should put me around 10to1.

thanks

 

Mill em .040.

 

my engine so far.

engine so far...
built up, almost done installing trans, and getting ready to drop in.

 

The fun will begin soon