Help. Engine not running right

[twoskies]

Hi
Ok. My truck is a 1972 c10. With a 1979 Chevy 350/4 bolt. Hei. New plugs plug wires. Was running ok to drive. But not quite right. Switched the brake booster to manifold. Capped off the carb outlet. Had the carb rebuilt. Made an improvement but the 4 barrels were not kicking in. Had my carb guy stop by took the carb to check. Changed the jets. Here’s where it went bad. Put the carb back on. Idles great. Can throttle up in neutral. Sounds great. Put in gear. Starts stalling and almost dies. Carb guy gave me a known good carb to try. Just slightly better. Still can’t drive around block. Here’s where’s I went back to basics. Changed plugs again. Checked timing. 10 advance. Put brake booster lines back to original. Put original carb back on. Still runs good at idle but can’t drive anywhere. I do have a good hei from a corvette I might try. Next. Any help appreciated