1978 GMC Truck - stumbles and stalls at idle

Engine Details:
Recently rebuilt 350 cc
Edelbrock 650 cfm carb
New plugs, wires, distributor, brake booster
No obvious vacuum leaks (tried propane test around vacuum lines)

Symptoms:
Truck starts up immediately
Drives smoothly
When idling at a stop light in gear, truck will start to run more rough
until it stalls, then will not restart without "priming" the carb. (I carry
a tin can and jerry can of gas with me, and can get the truck to restart if
I pour a tiny bit of gas down the carb throat). It will idle for longer if
I take it out of gear at the stop light, but eventually will stall still
(and be impossible to start). If I take it out of gear and give it a bit of
gas to keep the idle up, it is fine. This makes waiting in a drive through
very inconvenient. Before I started carrying the gas an tin can with me, I
actually had to get PUSHED through a drive through line up.

I thoughtit must be a vacuum leak, but I could not find one and it seems
like the hard to restart problem would not point ot a vacuum leak. I'm
thinking it might be some kind of vapor lock, but the gas lines haven't been
moved recently, so I don't know why it would start now....

Any ideas appreciated.

Eric

It sounds to me like the idle system on your carb may be a little off?
Edelbrock probable has a web site and you can email them your question.

One of my kids had a problem with a rochester carb, wouldn't start unless
he primed it. It would run and idle ok after started. He carried a can of
starter fluid with him. He didn't live with me. The last time he had a
problem, I went over, took the air horn off the carb, the float bowl was
empty.

I put a carb kit in it. It worked ok after that. If you think it is a carb
problem, talk to Edelbrock.