So I've got a bone stock LM7 motor and the heads are coming tomorrow off for lifters and cam in preparation for the turbo. I plan to have a valve job and guides done on them at the same time, but I'm wondering about doing a mill or using a thinner headgasket to bring compression up to 10:1. Has anyone done this and what was your method?

 

Can't do it with a headgasket, you'd need to mill the heads a lot to make a .5 compression increase unless you had 863's. What head do you have on it now?

 

Heads are 862's. A .041" thick gasket will drop the compression quite a bit no?

 

stick to 9.5

 

Truck will be run on 100% E85 and I was thinking a half point of compression will help with low end torque.

 

not as much as you think it will in that case, choose a different cam to bring torque in

unless you have a good tuner

 

I will be running the Tick Stage 1 4.8 / 5.3 turbo cam which is advertised to help with low end, we'll see. Ok George I'll take your advice and have them do a basic surface and valve job on them. I'm sure they'll need guides at 145k as well.

What headgaskets should I run? I have LS9 gaskets but the bore size is way larger on the LS9 so I think there are more ideal gaskets out there. I also have 5.3 GM replacement gaskets (same as LS1 I believe).

 

Ls9 gasket will do job...

 

Usually the Powdered metal guides in these heads are ok.

 

Even after 150k ?