Thanks,
I picked up a 390. The silv-o-lite pistons they use in it are rated at 10:1. I'll CC the chambers and cylinders to see what I've got. I'm just gonna polish the chamber, sand sharp edges on the piston reliefs, and maybe do a little bowl blending before I bolt it all together. Maybe that will help to prevent detonation at the higher compression being it's going into a truck.