360 Advice Needed - Autocross / Street Engine Build

Have you measured the volume of the chambers on the new Edelbrock heads yourself? Sometimes they can vary from advertised spec. I didn't quite understand your first post did you mean the engine is already assembled with all those parts?

Your short block is like a 360 I did, same pistons but they weren't .005" above deck, was your block decked? Is this something you or your machinist measured after assembly or is it based off just numbers-crunching? Also I think the Fel-Pro #1008 head gaskets would be close to ideal, .039" compressed thickness on those.

That Comp 275DEH you have might work well with some 1.6:1 rockers to bump up the lift, large split pattern is nice for manifolds. And I agree with the lower converter stall and taller gears in the back, 3000 RPM stall and 3.91 gears is more of a drag racing setup IMO.