Quote Originally Posted by lahrs37 View Post
I got the cam in a package deal that included the heads and intake from LMR. I am not even sure if they sell cams for the earlier 302s.
Very likely it's the HO firing order. That's the norm with aftermarket cams. I would be quite surprised if you have the old firing order. I'm personally not familiar with what affect this would have, if any, on the Ford EFI. Harmonic balancers shouldn't slip if installed correctly. There should be a Woodruff key (half round looking piece of metal) in the slot between the crank and balancer. Hopefully you installed that when assembling the engine. It insures the balancer is in the right location plus keeps it from slipping.