Hey guys I just swapped from TBI to a Holley 600 VS on my '91 RS. I've heard you have to swap the gears on an older HEI to run w/ a roller cam. I removed the gears from both dizzys: the TBI CC one and the older coil in cap vac advance one. Both appear to be made of the same stuff. The metals look alike and a magnet sticks to them both. The only diff. between them is that the CC dizzy has a smaller hole in the top where the dis. shaft fits through and then it steps to a bigger size half way down. The older HEI is one size straight through. Should I just run the older Hei w/ the gear that orig. came on it or should I drill out the TBI dis. gear and install it. Any help would be greatly appreciated since my car is'nt running right now and I have to get it going this weekend. Thanx

 

You should use a gear made for a roller cam. The factory did some surface treatment on them to help them last.

Something doesn't sound right, though. Any chance you could post a pic of the two gears & shafts?

 

You can run the HEI with the gear that came on it. There is no difference between factory roller and non-roller gears.The roller cam gear change only applies to aftermarket billet roller cams.

 

Thanx Jester, thats what I'm going to do. They looked to similar to be made of different metals.