Cast Iron? Who wants cast iron? LOL Umm..............2.02" in a magnum, got to be best iron for the $ IMO. They have alot of advantages over old J heads etc. Better chamber, better wet flow, better exhaust (maybe LOL), lighter valves, round lock grooves, 10 valve cover bolts, just alot better catsings, hardened seats etc etc etc. Magnums are "the deal" IMO. Stuff an AMC pushrod oil lifter in it, hollow pushrods and run 'em.