Hey Mike, i purchased a 1996 Chevrolet Suburban with a 7.4 litre and it came with the Whipple supercharger allready on it. On the upper half of the plenum,underneath where the supercharger bolts on is a vacuum port. While during a disassembly to reseal the intake, i found this port was not capped or a vacuum line attached to it. The port is about the size of your finger.Do i cap the port or does a line need to be used on it? And where would that line go to? If you or anybody reading this can help, THANKS!!!!!!