Purple Shaft or NOT?

Sportman said
Rumblefish360: I purchased these heads about 3rd down the line from the builder. They were fresh (new valves, guides, seals & springs) when I bought them and looked like the runners had been worked and polished and the intake gaskets matched. I have no idea what they flow.

OK, sounds good. On builds like this, I like to know where the heads stand. It helps in cam selection. Also, what your idea is for what you want, the target goal of the build is really helpful.

I like to run a split duration cam to help the engine breath better and extend the power band. Duration in the RPM range of the intended operating perameters of what your doing. As much lift as the head will take until the port stalls. Centerline goes down with engine size.

moper: The more I read about the mopar purple shafts, the more I run into people that dislike them. There are also some out there that love the mopar cams. I was leaning toward the Lunati 60404 prior to talking with Indy Cyl Heads. I am running power brakes so vacum is an issue. The block is going in on Monday so should I will have them 0 deck the block? The heads are fresh and cc'd @ 71. I would like to go with different heads in the future (when $$$$$ allow) so I don't want to get CR to high at this time??

I like the Lunati line as well as a couple of others. As long as you can run pump gas with the iron heads, you'll be fine when the switch to aluminum comes around. The bigger the cam, the more C-ratio you can run. Lower the centerline, the more ratio you can run. These two factors bleed off compresion at low RPM.

What ever you end up with, the distributors timieing is what will allow you to run 91/93 octane without issues. You have to take the time to dial in the distrib & carb to get it to run not just well, but at it's best!

It is possible to run a 10-1 on 91 octane with big-ish street cams if you take the time to dial it all in.