Originally Posted by Gen1dak
Yeah, sounds like a fuel issue. Ditto on the choke, but beyond that, it sounds like vapor lock. you referred to the "trash" carb as an AFB, that means it's not the original, so even rebuilt, there could be problems with it from sheer age if nothing else. The AFB is aluminum, and your average 360 isn't gonna generate enough heat to cause problems, but the fuel line near the engine could be an issue. This really shouldn't be an issue either since the fuel return line was introduced to alleviate this problem. Is the fuel return still plumbed in? If it is, a quick fix would be wrapping the line in a couple wraps with aluminum foil. If that solves it, you can work out re-routing for a permenant solution. Could be fuel delivery, maybe the pump is getting tired. Electric fuel pump to help out? Are you saying there's an electric pump in tandem with a mechanical pump or just an electric pump. I know the mid-80's was a crossover period for going to electrics, but not sure just when it was on every model before fuel injection. The electric pump could be possibly flooding the carb. Check fuel pressure.
Only vibration issue I've ever heard of related to the 360 is when using a zero-balance (318) converter. The lack of the external balance weight (needed by the 360) causes a vibration.
All vacuum lines and return lines related to the fuel delivery and vapor system are hooked up and have helped with performance slightly. The afb has a manufacture date of 10/95. And I live in an area of arizona where the nominal summer temp is mid 90's, so things definitely get hot under that hood.. There is an electric fuel pump assisting the mechanical, under the assumption that the extended wheelbase could be a little more than the mechanical pump could handle (we didn't put the electric pump on it, it came that way from the school district my grandfather bought it from).
We manage mobile home rentals so this truck is essentially perfect for my dad as it has the room to carry all his tools, materials, air compressor, generator, etc. But we don't have the budget to be replacing the carb or anything huge like that, so I'm trying every simple, and essentially cost free ways to get this beast running better.
Oh and as far as the choke goes, it does stick, but after rebuilding the carb and fixing a few vacuum lines, it doesn't seem to be misbehaving, could it be terribly out of adjustment since it has an electric choke?