vacuum advance help?

i have a 1979 chevy malibu with a chevy 350 and an edelbrock top end kit installed. its amazing how i can fix anything else but i can't figure out why my vacuum advance isn't working at all.
anybody have suddgestions?

Is there vacuum to the diaphragm at idle or part throttle in neutral for starters?

Take off the distributor cap, hook a tube up to the vaccuum can on the dist and suck on it. You should see this metal rod that goes into the diaphram retract. If there is no movement the diaphram is leaking or the linkage inside the dist. is stuck.

If it does move then you have no proper ported vaccuum source. Use ported vacuum, not manifold vacuum.

These cars had a thermal vacuum switch on top of the stock manifold, which is notorious for getting stuck, leaving you with either no vacuum or just manifold vacuum. Bypass this switch, if it is still on your engine.