[turbotodd69]

Also check LS4.com. If you're worried about keeping DOD leave the heads alone. If not look into L87 intake and head swap they're from the LS7. They are usually good for 45-50 whp but you will have to modify the intake manifold. The LS4 Intake manifold is shorter than the rest of the LS series motors. I also agree with check LS1tech.com. I know I own a 13 LTZ but I am a former owner of a 2006 GXP and a 2007 SS I have a little experience with the LS4.

 

[turbotodd69]

You're right Dwayne 7 liter heads are overkill on LS4 and there would be a good amount of modifying to get them to work. I just looked into L87 swap when I had my GXP. L87 is how GM performance lists the 7 liter intake and heads combo to buy from them. The swap has been done on a LS4 before. I'll see if I can dig up the link. Check with F.A.S.T intake manifolds too they were starting to mess around with the LS4 when I had my GXP but you have to remember I had my GXP from 2006 to 2007. I'm just trying to share what I learned then.

 

[turbotodd69]

Like I said I agree with 243 heads. I loved them. I had so many people with LS1 motors ask if I modded my GXP and changed the heads if they could buy them from me. I think you're right he should get a good port job on his stock heads and call it a day. The intake manifold doesn't do those heads justice though and I know people with LS4s have put F.A.S.T intakes on them and made some good power. They have also went with larger throttle bodies. When I had my GXP nothing was out yet for them let alone tuning that's when GM just started using the CAN BUS . I guess that's what it was called. I don't know much about tuning OBD2. There is a lot more out for the LS4 motor now including some good tuning.