i am going to put a zz4 cam in my 89 GTA with 89 corvette heads.I was told the heads have been worked for the higher lift cam. (this may be a lie) if not do I need .100 longer push rods? Or should I stick with stock?

 

If you're buying push rods anyway, I would suggest longer ones than stock. The stockers are probably adequate but on the edge of being too short with the lobe lift of that cam. .100" long (that would result in 7.400") would be OK.

To be certain, you should get an adjustable push rod, and check for the optimum length.