I have a 505 Stroker in my 1971 Challenger. I put a new viscous clutch fan and Mopar shroud from Mancini. Still overheating. I was doing some reading and noticed the fans should be 50% out of the shroud for maximum cooling. I have no spacers on the fan and the fins are right at the edge of the back of the shroud. Am I supposed to cut the shroud so more fins are visible?