Purple Shaft or NOT?
All of the purple cams were completely redesigned in the late 80s, so their technology is not that old. Whereas many cam companies grind camshafts for Mopars, only a select few grind them with the .904 lifter bore in mind. The Mopar Performance line of purple cams is one of those who does. I like a lot of the Comp grinds, but the truth is, they are all ground on the same profile as all of their chebbie and phord cams. All you have to do is look at all the specs. I don't think Comp knows how to grind anything that ain't on a 110 degree lobe seperation. lol A lot of people swear by Hughes cams and while I believe they are some very knowledgeable people there, I haven't heard of very many people running them. Having a larger diameter lifter than any other small block and most big blocks means that they can stand more lift per an equal amount of duration in comparison. Does that make sense? So, honestly, the best and only way to get every ounce of power is to do your homework, find out all of your available specs and get something custom ground. Short of that, there are the off the shelf cams ground for the .904 lifter bore, and there ain't many. MP and hughes are the only two I know of, actually. Any of them will do it but only those two offer it off the shelf as far as I know. All camshafts should be degreed in performance applications in the end anyway, so what difference does it make there?