i'm trying to calculate the compression on the factory l98 shortblock i will be ordering soon..

it will have afr 190's with the 68cc chambers and a felpro 1003 head gasket... the gasket has a 4.166 bore and a .041 compressed thickness......

i figured a ballpark estimate would be around 9.0:1 but i would like to know what it will be exactly.....

 

how you going to know how far in the hole you are? guess? as a rule pistons with 4 valve notches will run around 4cc

 

well most factory 350's will be down the bore about .025... it varies..... i'm trying to get those most accurate calculation i can.....

 

I've measured from just under 4ml (maybe all the carbon wasn't cleaned out) to just under 6ml on some "factory" 4-relief pistons. Deck height is another factor, as well as top ring depth if you really want to split hairs.

 

lmao@ your sig vader

 

Heres some numbers.

Bore = 4.00"
Stroke = 3.48"
Deck = .025"
Head cc's = 68
Valve reliefs = 3.4 cc's
Head gasket dia. = 4.166"
Head gasket thickness = .041"

C/R = 9.36 to 1

Auggie

 

i don't see how it have 9.3:1 when thats what the factory l98 long block is rated at with 64cc heads...... maybe the head gaskets is thin enough to take up the difference?

 

Boy, I don't know but if the L98 eng. with 64cc heads and a .060" head gasket that eng. would have a C/R of 9.34 to 1

Auggie