Been through everything, What am I missing?

[whtgmc68]

I had nearly the same problem with my truck when it still had the 350 that was in it when I bought it. I replaced the carb, fuel pump and filters. Turned out there was so much gunk in the fuel tank that I just replaced it since it was about the same price to have the orignal boiled out and properly cleaned.

Never had another problem and when the engine finally got a proper flow of fuel, it ran so well that I almost hated to replace it with the 383.

[ZEKE68]

Had a very similar problem on a 55 chevy I had once. Turned out the ballast resister had gone bad and was sending 12 volts to the distributor. These trucks have a resister wire instead of a ballast I believe, so it's likely not the same problem. But as stated ignition problems can seem like fuel problems.

[AASmedic]

Originally Posted by ZEKE68

Had a very similar problem on a 55 chevy I had once. Turned out the ballast resister had gone bad and was sending 12 volts to the distributor. These trucks have a resister wire instead of a ballast I believe, so it's likely not the same problem. But as stated ignition problems can seem like fuel problems.

Not an issue here. I have an HEI ignition.