Quick background, got a LT1 motor along with the car with somewhat unknown history, I had my cage guy handle the driveline install. Had the heads taken off and resurfaced, valves were checked, LT4 valve springs put in, threw it back on the block with those super awesome Cometic gaskets.

Cooling system seemed to do well but got worse over time. Boneheaded mistakes on my part led to it running hot too many times (not bleeding air bubbles correctly, not sealing off the radiator soon enough, stupid ducting decisions, not backing off when it got hot, etc), and now I suspect a leaking headgasket, motor will not stay cool on track. The crankcase is collecting a lot of steam during idle that does not "go away", I am losing coolant somewhere inside the motor, pressure testing to 20lbs with hot coolant shows no hose/fitting leaks, and i swear i saw a few drops of oil in the radiator.

I borrowed a leakdown tester and will test some or all of the cylinders before I go ahead and pull the heads next week.

I had done some reading up and see that the Cometic gaskets require a VERY smooth finish? I've got a spare set of regular Fel-Pro 9966pt that I understand to be more tolerant of rougher deck surfaces/finishes. Would it be worthwhile for me to just slap those on and continue on?

I've got a pretty good idea of what all it would take to R/R the heads, but where I am fuzzy is the best procedure to prep the block deck surface while it is still in the car, and whether or not I should apply any copper sealant to aid in sealing.

Any tips/advice on what else I should be doing?