Carb, I think, question

[phat46]

Start your car and cover most of the carb with your hand, and see if it runs better. You can also close the choke butterfly most of the way.
If the engine runs better, you have a vacuum leak.
.

I'll give it a try tomorrow...

[Thunderstruck]

I just replaced the floats in my Edelbrock 750, bought it in 88 and one of the floats started sinking a while back.  Dried it out and soldered it back up, that held for a while but it sank again so I just put a new pair in.  Prior to replacing them it idled horribly and would die with almost any load, unless I kept my foot in it and even then it was easier to push the car than move it with the engine.  Easy to diagnose, shake it and you'll hear the gas in it.

[phat46]

I just replaced the floats in my Edelbrock 750, bought it in 88 and one of the floats started sinking a while back.  Dried it out and soldered it back up, that held for a while but it sank again so I just put a new pair in.  Prior to replacing them it idled horribly and would die with almost any load, unless I kept my foot in it and even then it was easier to push the car than move it with the engine.  Easy to diagnose, shake it and you'll hear the gas in it.

Actually, I think i have fixed it. I have never touched this carb with a tool, the motor came out of a donor truck and hasn't had any mechanical work done to it, other than to make the ignition work after the Duraspark box died. I noticed that the idle adjustment screw wasn't touching the linkage and that seemed weird so I turned it in about one turn so that it contacted the linkage and the problem went away! This vehicle isn't road legal so I can't really test it well, but it does idle now; I hope it really was this simple....but...I can't understand why it was running good a couple days before this started and i had changed nothing....