Are the aluminum Magnum Mopar Performance sold cylinder heads too rare to find?

Seems like I remember Larry Shepard writing they were “about” 52 cc combustion chambers and the deck could be milled a lot.

Didn’t Ebogger find some aluminum MP Magnum cyl heads for the Magnum 5.9 V8 he transplanted into a v6 Dakota?

Long ago we had a Mopars thread about whether aluminum heads
affected either max hp or max bsfc,
my reading of what reliable data there was led to concluding no measurable differences.

Mazda’s 14 to 1 engine used aluminum heads.

On a 5.2 Magnum I would stay below 12.7 static cr

Are there any production 4” inch steel pistons out there for industrial engines,
like natural gas or 2 stroke heavy bunker oil?