I have just found out that my heads are Vortec and the problem according to Dustin is that the exhaust valve is too close to the center of combustion and the heat from same is picked up by the exhaust valve and it burns. Porting the heads may help but the water jacket is thin in the same area needing relief. I wonder if the heat created by the whipple (even with inter-cooler)exacerbate this problem where as the procharger (cooling after compression) will be less of a problem. Procharger people say that the 7.4L MPI is a good motor for a mild boost (3-4PSI). I know somebody out there has worked through a successful Procharging of this motor.