i've read another members thread a minute ago. i didn't want to hijack it, but wanted to post my troubles with my '66. he seems to have the same issues.
bone stock 352, but with open element air cleaner (thank you, Kalib).
now, the following work was done months ago and the truck has run flawlwssly ever since: new points, plugs, plug wires, condenser. carb rebuilt (stock 2 bbl)
again, this truck has run flawlessly up until 2 weeks ago. here's what happened:
i drove to the junkyard without incident. spent 3 hours there and got into the truck to head back home. started up without issue, but it kept stalling. i had to keep my foot on the accellerator pedal while stopping at stop lights and traffic all of the way home.
this truck will NOT run without almost full choke. i haven't started it since that day two weeks ago. i went outside to start it just now. same thing: it will not run without full choke.
i'm frustrated because i never touched a thing from the time i went to the junkyard until i got back in it to drive home. it drove flawlessly to the junkyard.
what the heck could have changed while the truck was sitting?

 

When was the fuel filter last changed? It could have accumulated enough trash to cause it to plug.

 

The fuel filter was changed before I rebuilt the carb. About 500 miles ago. I installed it before the electric fuel pump. Changed out the fuel lines. Cleaned the fuel tank (which was stored dry and had zero dirt in it) before I installed the fuel pump.

Man! I am stumped.

 

2 things... 1) check the choke adjustment...could have slipped or got stuck and 2) check your ignition points gap.... they could have slipped especially if you did not place a tiny drop of Teflon oil on the distributor ... where the points rub against the shaft...that will cause excessive wear.

 

Choke seems to be ok. But I will check the points. Good call on that.

 

Why the electric fuel pump? Disconnect a fuel line and stick it in an empty jug and turn the pump on. You need at least 1 pint in 20 seconds.

 

Electric because a manual pump will not work on this truck. Yup....you read that right.
when I bought it, the PO said that it eats fuel pumps. I thought "yeah, right".
The existing pump did not work. Bought a new one, it didn't work either.
I think the eccentric is wonky on this truck. So, I installed an electric pump.
Runs at 4 psi approx

 

If you're having to use the choke, you either have a jet or jets clogged as it's starving for fuel... I have had floats get stuck in the up position stopping most fuel flow.

 

When you have nearly full choke you are creating enough vacuum under the choke plate to pull fuel from the booster nozzles. That tells me that the idle and transition circuits aren't feeding enough fuel. Normally low fuel flow manifests itself at highway speed, but you have to start somewhere.
Normal fuel pressure is 4.5 to 6.5 PSI. Pressure and flow are two different things.
Is the pump suppling enough fuel at the correct pressure?
Yes= then the problem is in the carb.
No= then there is a filter, plumbing or pump problem.

 

Well, like I said the pump, filter and fuel line is new.....perhaps 500 miles at the very most.
the tank was cleaned and had not even a thimble full of dirt.
I have an adjustable fuel regulator set at 3 lbs i believe.
I'm gonna tap the fuel bowl to see if the float is stuck.
This is so frustrating.

 

Don't discount the possibility of a condenser that's gone bad. One of the most insidious of devices that when working right you never think of it and when it's not working right you never suspect it, but it CAN be the cause of numerous WTF times to be had. Everything from not firing to lean or rich conditions to engine stumbling, etc. etc.

 

Don't get frustrated.
New things are sometimes bad out of the box or go bad within days. I had to change a condensers within two days on my 289 some years ago.
Checking the fuel pump is a good first step, I would also check the ground cables to make sure the pump has good contact.

 

i actually do have another condenser that i can install. i'll be doing that . i also sprayed carb cleaner at the connection between the PVC hose and the base of the carb. i got a slight rise in RPM, that hose is probably original. i have a new one on the way and should be here today. yup....it's very tough to NOT get frustrated. i use this truck to pick up the parts that i'm gonna swap into it. it probably knows and is fighting me the whole way.

 

well, here is the update to my idle issues. thank you to all of you guys that gave some excellent advice. i just knew it had to be carb related. so, i took off the nozzle bar and venturi boost assembly and exposed the jets below. i assumed that there might be something blocking the main jets. without being ble to take them out, i inserted a carb cleaning pin into both jets to clean out any offending material. buttoned it back up, started it and it ran like new. just like before i had my issue. apparently something got into one of the main jets and clogged it. it idles perfectly
i just wanted to post this in case someone else ran into something similar.