Rpm 340 Cyl heads on a 318 !

If 'twer me, I'd seriously look at some Chevy rods (made in a lot of lengths) and pistons, to push a 4.000" flat top piston .050" or .060" above deck for those heads. Or, mill the daylights out of the deck with a flat top 318 pistons to get it way up. That'll put you in the low-mid 11's SCR range and give you quench with that head. This assumes that SCR is adequate for your needs. I'd expect that to be a higher SCR than a milled 318 dome, simply because it fills that milled space in the 760179 head more completely. The SBC eyebrow position might be a bit off and require some work.

Milling the .060" 'open' chamber completely off of the Edelbrock head would do the same for SCR. Chamber volume would then be around 55 cc's. Not sure if that causes other issue with the valve area to drop it that close to the head; seems like that has been mentioned.