I’ve got an 01 LM7, it’ll be FBO with a cam (224/232 .553/.553 111). I picked up a set of 243 heads from a LS4 and I’d like to be able to gain some compression back from switching to these heads.

1. Would .030 off the heads and a .040 gasket be a good combo?

2. Which head gaskets will work best? I’ve read of people using LS1 and LS9 head gaskets for a LM7 with 243 heads.

 

wallace racing has some good static & dynamic CR calculators you can run your options through.
another thing to consider is that the LS4s had flat-top pistons (like the L33s & Gen4s), whereas your LM7's got dished.

and i hope you've got a stall & an intake that flows better up top to take advantage of that much cam.

 

I’ve got a 3600 stall converter and a ported NNBS manifold, hoping it’ll run decent for a little N/A 5.3. I’ll check out those calculators, I’m hoping for 9.5 CR or better

 

You’re going to have to rev it to get good power out of it.

 

Yea, 243's like their rpms...