I spent a lot of time trying to measure compression height and dome volume of various hipo 273 pistons. Unfortunately, I didn't have a factory piston to measure. But I did compare Egge, Kantor (Rebuilder's Choice) and some TRW forged pistons that are no longer made.
http://www.forabodiesonly.com/mopar/showthread.php?t=199120&page=3