Does the stock cam in the ZZ502/502 have enough vacuum to run power disc brakes ? And, where did you run the power booster vacuum fitting that screws into the intake at ? Due to the placement of the threaded hole behind the carburator, there is not enough room to srew in the factory type vacuum brake fitting that has one threaded port for the vacuum brake signal and one slip-on port for the transmission vacuum modulator. graemlins/clonk.gif Is there a common fix ?

Kent
'68 Malibu ZZ502/502 :D
ACES #5102 graemlins/thumbsup.gif