Which heads are best

Pretty much every Mopar head, big or small block I've ever checked was larger than the advertised specs said. I'm sure others have had different results as was already posted. That's because even chamber to chamber you can get some wild fluctuations... That's just factory casting QC, old valve jobs, etc. If you stay open chamber, they will be fairly big. Have them CC'd, and made to be what you need them to be. I think anything over 10:1 static will want a cam around 230° @ .050 at minimum to keep out of detonation with some available pump swill, even with careful tuning. Not because the combo suck - because the fuels can be that bad. Personally I don't consider a 900-1000rpm idle as liveable in a cruiser but maybe you're good with it.
Really - lose the requirement for power brakes and you'd be miles ahead of where you are now.