350 carb/fuel problems.

1992, GMC Sierra. I recently took the 4.3 V6 TBI out of my truck and swaped in a carbuerated 350 out of a 1979 CUstom 20 HD. When i start it, it idles at about 1000 rpms, and in nuetral it revs up fine (with a little back fire- but i think that should be normal with the loud exhaust i have on it). but when i put it in gear and drive it, cant put the pedal down further than 1/2 way and theres really no power under load. its almost like its out of gas, but i know it sgetting a steady fuel supply.

Any help or ideas will be apprieciated.

did you compensate for the difference in fuel pressure of fuel injection vs carb. if not you need to and probably need to check carb float position now. you are probably flooding. just a thought. let me know.

i disabled the elctric fuel pump and bought a new mechanical one. easier that way. turns out it just needed to be cleaned and have new gaskets installed. the swap is 100% done now!

good job although thats a q jet correct?? I had 70 caddy coupe conv pulled q jet put edlebrook on got more power and better gas miles that 472 lit some rubber hated to sell. food for thought now that you made switch. no more worry of elec fuel pump crap!! I like old school