My 390 is one of the NASCAR racing carbs. It doesn't have ANY vacuum ports. It is a double pumper with jet plates and no power valves. The PCV is tapped into the intake manifold plenum. I have a tee in line to supply vacuum to the advance servo. I fabricated a reservoir for the vac. advance and I'm adding the check valve as I said.

I am not really all that displeased with how it is working now, BUT!! if I am not more satisfied after adding the check valve, I will drill a vacuum circuit for ported vacuum later this summer.

Last edited by Blackwater; 03/03/17 05:00 PM.
Never use a minor caliber bullet on a major caliber adversary