magnum heads are 63CCs? I have never had a set CC'd but all the printed literature I've seen, says they are 59-60 cc. except (1) set of MP ones which according to their catalog is only like 53 CC. How do these numbers compare to a set of '163 318 LA heads? (that's what's on the engine now) I mean common printed numbers; I know that I won't know exactly what "this" set reads w/o CC ing them.
On the quench, unless my pistons are heavily coated w/carbon (possible because of the oil usage thru the guides) this is a dead stock shortblock and I do not have it apart yet but we all know that by the 80s (my truck's an 83) Mopar was not into zero-decking their pistons, don't we? so even with the thinner head gaskets I have bought I doubt I'll have less quench than you specify.

Also are these slanted spacers available somewhere, or are they something I'd need to make (or have made by a local machine shop?)

Oh and thanks for the help so far guys. I am planning on having all I need for this head swap by the time my wife has her elbow surgery done, so I can have a "chase vehicle" here to run for parts with, so I have most of the month to figure out what I'm doing with this, manifold wise. I'm leaning towards one of Hughes' Edelbrocks he advertised on here a while back. but would loke to experiment wit different ideas while it's apart for future reference.