Thinking about boosting my dd lq9 an running 7lbs, I dont want to kill my motor right now anyways that is lol. Stock internal truck it does have a tbss intake and ported 862s with PRC 660lift springs, ferrea 2.02 intake and 1.57 exh valves, titanium retainers, multi angle valve job.. milled .030/ now have a 58cc combustion chamber. My question is I have stock 317s, should I put them back on or should I leave the 862s an put thicker gaskets to lower the compression ratio down cause I think I'm running 11.5:1 right now thoughts? Thanks for the help.

 

7-10 pounds with good fuel and tune is safe and reliable no problem ... definitely get the cr down ... I ran 10.4:1 cr and 10 pounds and I ran good but I struggled to get 18 degrees total timing even with meth. Made awesome torque but was always on the edge of detonation. I just dropped mine down to 9.9:1 so hoping to squeeze few more psi.

 

How think of gaskets would I need? Other question is will the stock 317s perform as good as these 862s ?

 

also could I use 42lb injectors on 7lbs ?

 

42's will probably not work...I ran out of fuel on my lq9, cam, and procharger with 8 psi....swapped over to some 60's

 

any thoughts on the heads?

 

Depending on the work done to the heads, they should outflow a stock set of 317's. You are playing with fire staying with the 862's though, that compression ratio is too high. Also, stock 317's will flow well enough to support some big hp numbers on a turbo 6l. I would stick the 317's back on if you want it to last. Also you need to go with the 60's the first go around, you will need them.

 

That kinda comp on 10 lbs is in the iffy neighbor hood imo. If you boost it with them heads I would stay under 8 lbs, unless your spraying meth and the tune is SPOT on on fuel and timing. If you want boost swap the heads to the 317's and have at it. JMO.

 

specs on the 862s are in the first post , I plan on getting thicker head gaskets to lower my compression ratio to a safe level on the 862s, as long as they will be safe an perform better then the 317s. I want it to last so if the 862s will be to risky I will go with with the 317s thoughts? I'm only planning on running 7lbs.

 

No flow specs on the heads... You cant lower your compression a significant amount with gaskets, so thats not gonna cover you like you think. Running 5.3 heads that have been milled quite a bit on a flat top 6l with boost is dangerous. Plain and simple.