98ws6blk

How much should I mill 799 heads to reach 10.9 compression if using the gm mls gaskets?

I found a chart showing the chamber cc's compared to compression, but wasn't sure how to translate to milling...

427zm

iTrader: (9)

I just got my 799's back from Texas Speed, and didn't mill any! Instead, I'm using the Cometic .040 gasket set as opposed to the MLS gaskets. My static CR will be 10.95 when done, and I will have added quench, which helps against detention and I won't have any PTV issues.

spicebird98

iTrader: (10)

yup as said ^ .40 gasket will put you right around where u want to be

98ws6blk

Yeah I know the .040 gasket is an option, but I've got to mill it some to clean up the surface since they are used heads. So wanted to see how much it would be just milling.

A.R. Shale Targa

iTrader: (2)

Very good and efficient way to increase compression ratio BUT a small corr-
ection....quench is the distance from the piston @ TDC to the cylinder head.
A .040" gasket is thinner which reduces that distance (CC's of volume)..

If you are using factory gaskets, and assuming the heads have never been
milled, you'll need about 61cc chambers. So starting from 64.45 cc, a .021"
cut should put you where you want to be..this will also affect push rod length

mrgwrnch

I have a new set of 799's. I just cc'd them at 67cc.

A.R. Shale Targa

iTrader: (2)

strange that they are off by that much....foundry casting differences....
maybe they just mill them less to save a few bucks....