smoothzee

Can anyone tell me what the compression ratio would be for LQ9s on a 2001 LS1 block. I have an opportunity to obtain a good set, but I don't want to lower the original LS1 compression ratio. What could I do to bring the compression ratio back up to 10.25:1. Any info would be greatly appreciated.

Smoothzee

jrp

iTrader: (16)

you'll need to mill them .030 to get back to stock compression.

smoothzee

Thanks for the info! Does the intake side have to be milled to accommodate the intake? What do you base that number on? Not trying to be a jerk.......just need to know so that I can make an intelligent decision. Thanks!

LSonederfull

No machining on intake face needed, 6.0 head is 71cc est. so .030" mill will bring chamber down to 67cc est . that your 5.7 heads were. You can also gain some compression and tighten up quench by using Fel pro #1041 gaskets, only .041" vs. stock gaskets .055" thick.

TigerFan187

iTrader: (1)

I will be putting LQ9 heads on my LS1 here in a few weeks. I cant remember the CR I will have but I will post it when I find my notes! I would buy them if the price is right because you can always sell them if you dont end up using them!

smoothzee

There is a formula that I got off of one of these posts. After using the formula
I arrived at 9.7:1 compression ratio based on the 71.24 combustion chamber of the LQ9 heads. A mill of .030" will raise the compression ratio to 10:1, or at least that's what the "pros" tell me!

smask04C5

iTrader: (1)

for every .006 milled, removes approx. 1cc. from combustion chamber