390 w/open chamber heads

I recommend decking the block the minimum amount to obtain equal deck height and an ideal cylinder head mating surface for any rebuild, if your build requires a zero deck...so be it.

Personally I shy away from zero decking due to my indecisive nature, I try to reserve the option of change my mind at a later date and once you remove material from the block it's gone forever.

I'm far more likely to try to choose pistons, heads and even head gaskets that will give me my desired compression ratio with only removing the minimum amount of material from the block.

This is a lot more work, and truth be told...sometimes more expensive.

for example, my 30 thou oversize 318 has a +.007 deck height (this is still enough for a good quench) and dome top pistons. 66.5 cc heads and compression ratio is in the mid tens. The block is still as close to standard deck height as it can possibly be having only been surface ground for the mimimum amount for blueprinting.