COBRABRAT2

I have found some World Products Windsor SR. 64cc 2.02 valve heads with about 600 miles on them for 600 bucks. I want to put them on a stock bottom end (with Arp rod bolts). I come up with a compression ratio of 10.06:1
This is using 4cc as the piston valve relief and .01 for deck clearance. Does this sound right? It seems high to me. Stock is way lower than that.

any help would be appreciated.

decipha

IIRC the 87+ e7 stock 351w heads are 65cc combustion chamers and have an 8.8:1 CR

I pulled those number out my as$ but to the best of my knowledge they are correct

COBRABRAT2

thats why i think my math is wrong:

4x4x3.5x12.874= swept vol 720.74
64+9.5 (gasket)+4cc(reliefs)+2.05 (deck clearance)=79.55
800.29/79.55=10.06

am i doing something wrong? is the relief number wrong or deck clearance wrong?

MadMan@TheWheel

One, where in the hell are you getting that number?

If what you have done is correct, 720.74/79.55=9.06

Unless I am missing something, I have no idea how 64cc heads on a stock lower end can give you 10:1 compression.

r.barn

This is a good online calculator
http://www.csgnetwork.com/compcalc.html

I came up with 8.8 using following numbers, and that sound right to me.

4" bore
3" stroke
4.10 hg bore
.041 compressed thickness
64cc heads
-4cc pistons
0.010 deck height

COBRABRAT2

ok, its a 351W. doesn't that have 3.5 stroke?
here is where the numbers come from:
swept volume+total chamber volume = compression ratio
add720.74 to 79.55 which equals 800.29. then you dividethat by 79.55.But I see now that this gasket number I got from somewhere is WAY wrong. Either way, I got this info out of a HP book and it is way off i guess.

now i'm really confused.

r.barn

ok, oops, you have a stock 351 bottom end.

dont worry about all those formulas, just use the link.

with 3.5" stroke the 351 has, I came up with 10.1 compression
with .03 over bore more like 10.2 to 10.3

COBRABRAT2

k, thats very much. I'm picking up those heads today. I wish I could go all out for aluminum, but until i win the lottery, these world castings should be a hell of a lot better than stock heads.