Classic/Antique Car Repair: Carb. vacuum, manifold vacuum, vacuum hose

Question
Brad--I am replacing a R2GC carb. on my '58 Pont. with a Carter AFB 4 BBL copy (Edelbrock). The copy a has "Ported/ Timed" port above the throttle plates and a Manifold V. port below. My Roch. now feeds the dist. adv. with a port that is located on frt. rgt. corner part way up the carb. body. Which AFB port should feed the Dist.?
-----------Thanks  DLJ

Answer
Hopefully you still have the 2 barrel on the car. The easy way to check is to run the engine and check for vacuum at the port. If there is vacuum with the engine idling then the lower port or Manifold V port is the one to use. If the vacuum is not seen at the port until you are above idle then the timed port is the one to use. If the carburetor is already off the car, block the throttle plate open. Use a short section of vacuum hose on the port that was connected to the distributor and blow through it. With your finger inside the car bore see where the air is coming from. If it is above the throttle plates it is timed or ported and below is manifold vacuum.
Brad