I might be getting hold of a low mileage LQ9 with the 317 heads and was wondering what other heads would work on this to bump the compression up a little bit. Keep in mind I am working on a budget and will probably be keeping my 224 cam.... And Ive got a 150 shot going on it too

 

LQ9 is already 10:1 . That is more than a 5.7 LS1/LS6 . I would leave the 317 heads on it if your on a budget. They flow the same as LS6 head [317 has bigger cumbustion chamber] they are same head. LQ9 has a flat top piston so you get 10:1 compresion.
Your 224 maybe a little small for the more compression, bigger, much better breathing, engine.
I have found only two places that stock cams specificly for "N2O" and LS applications. They are not site sponsors, but very reputable companies. One of them recomends TSP for there tuning.

 

Actually, lS1's and LQ9's have the same compression at 10 or 10.1:1. I can't remember which, but I do know that they are the same. the 317 is the same thing as the ls6 head (243), but I think if you want to run a little higher compression you should mill the heads down ( they have huge combustion chambers) and run thinner head gaskets. Maybe someone who knows a little more will chime in

 

An LS6 has 10.5 to 1 compression with a 64.43 cc combustion chamber.

 

Just mill the heads a bit

 

I have the same questions! Searched and searched but havent found the answer I need......241 or 317's are my only option right now. Mill the 317's or go with 241's on a LQ9? how much should I mill the 317's for a 224 cam stall headers, bbk intake, Daily driver and no track time, want the best power I can get with what I have

 

keep the 317's, measure PTV, and mill the heads until you reach the minimum acceptable clearance

 

Don't quote me on it, but I think max mill is about 0.060". But that would give you a good ittle bump in compression.

 

0.060" I read some where in one of the many posts that pred said 0.014" would get me to around 10.5, if I mill them .060!!!!! I am really needing to know fast, I listened to some friends that said they are not good blah, blah, blah and I need to go with 241 or preferably 243 but the more I read the more I think I meed to mill them and run them. I posted them for sale on craigslist and I just got an email saying that someone wants to come pick them up ($200). Sell them and go with the 241's or mill them to get 10.5-9 compression ratio?? I am running Longtub, 85mm tb and intake, 224 cam, 3200 stall auto, most of the mods are in the sig. HELP!!

 

Stock for stock they will out flow 241s, milled ported they wll flow even better than milled and ported 241s...241s would be a down grade

 

^^ ^ agreed keep the 317s and mill them. DO NOT SELL THEM FOR 241s. if these are goin on a stock piston lq9 than mill the 317s. they flow the same as 243s and will get ur cr up to what you want.

 

Dont mill your head .060 thats for sure.

 

No I am not milling them .060" I work in a machine shop so I know that is a hell of a lot of material to take off the heads, I do need to figure out how much to mill them to get to 10.5-10.8 ish. Should I have them port, polished and milled or just mill them? If I have them P&P and milled I may as well get some 243's, but they will be stock 243 casting with nothing done to them....I need A

 

2cc for 10.5:1 ~.014

 

Lol sorry I wasn't saying to mill them 0.060", that is pretty much the max you can mill them....I've seen people want to try and get them milled to get a 60cc chamber and it can't be safely done, but you can mill them to bump up comp ratio....I hope that clears up what I was saying

 

what would an lq9 have with a 64cc chamber?

 

10.5 : 1

 

A thin gasket, and a cleanup on the heads and it's real close to the target.

 

I agree with this guy..

 

Oh look, another old *** thread revived to ask a thoughtless question....

An LQ9 with a 64cc chamber is basically same as an LS2, so the compression ratio would besically be the same as well. You could also search for the various online compression ratio calculators to see how different heads, gaskets, etc will change the compression ratio.