This is not exactly accurate. The MoPars are limited to a smaller .842 because in some class racing, the Chevy enghine can n to bore the lifter bore out to a .904 or even the Ford size. This is Chevy's way of limiting the competition and leveling the playing field. Truth be told, a .842 lifter can still get a pretty aggresive lobe ground on to it. To truly take advantage of the .904 lobe will produce a very aggresive lobe that most engine do not or can not take advantage of.
