Roundtop SUs on a 73 240Z with 280 degree Racer Brown cam.

Stock distributor with Pertronix ignition and coil.

Do I want my vacuum advance connected to manifold vac or ported vac?

I currently have a problem with hot idle, wonder if it is just lack of vacuum advance at idle?

How are y'all plumbed?

For the vacuum advance to work - it has to be connected to a Ported Vacuum Source. When you go to wide open throttle - vacuum in the manifold drops, while the vacuum signal right behind the carb. increases... So you connect the vacuum line to the rear of the front carb.

FWIW,

Carl B.