any aftermarket cam will have the pushrod oiling lifters except maybe mopar performance ones. everyone else (comp, crane, summit, lunati) lists the same lifters for AMC and chrysler.

w/o decking or new pistons, with the mag heads and stock LA shortblock, if you use the think Mr. gasket/MP head gaskets (.028" thick) and your mag heads are stock 63ccish chambers, you'll be at about 8.6-8.7:1 compression.

decking will most likely be more expensive than the cost of the pistons, but then, you probably would want to actually get the block bored if you're buying new slugs.

I'd be leery of even that much lift on stock mag valve springs. remember, on the magnum engine that will be .470/.470 lift. I'd use the GM 3100 springs/retainers with that cam.