it's funny the turn that threads can take. i assumed they were the new heads, it would be a strange circumstance indeed to end up with a set of those. but just a picture of the valve cover would show it.
i'm not sure i agree with the rodney dangerfield aspect. i know a guy who has a restored a990 belvedere, and it wins high awards every where it goes, (spring fling, mopars at the strip, the ohlone college show, etc...), and has been featured in one of the hot rod mags, (forget which one, but herb (scatpk) would know), in the last year or so.
thing is, you never know, funny things happen. the guy with the belvedere looked long and hard for the heads, and finally found them from some guy who was only willing to give them up when he knew what they were going towards: to restore an a990 to original specs. he wasn't going to give them up under any other circumstances, and they still cost a pretty penny.
herb can correct me if i'm wrong on any of this.
anyway, take your heads off and have them ported, the stock mopar aluminum heads don't flow worth a damn.