engine trouble!!! grrr

[BoeJaker1976]

OK, so with all the work ive done with truck, the engine is still running like crap. The engine use to work fine before the carburator went out. I relpaced it with a rebuilt qjet. I used a chiltons to figure out the vacuum diagram. I timed the engine to 8b, and turned the screws on the mixture to 4-4 1/2 out.
The truck is a 76 with a 350 and a 350t tranny and a 4b quadrajet. The HEI distributor was replaced with an MSD. The airpump and supporting emissions equipment have been removed except for the canaster. There must be something i missed some where or maybe something is in the wrong place. Here are the symptoms: During temp of 70 degrees or lower, the engine will start fine, but will soon die after. After it does start, it takes some time to warm up. After the engine warms up or when the tempurature out side is about 85+, it starts fine. Another thing it always does is, when im able to drive, and i put load on the engine (puting into drive or rev.) when i lay the pedal down lightly, like when i pull out of the drive way or slow driving, the engine bogs down and will die if i hold it there. But when i mash on the pedal its like theres no problem at all except at WOT. It'll bog a little there too. And today, it started back firing.
So i would really appreaciate any help or advice anyone can give me. Ive gone through the chiltons trouble shooting guide and i cant figure anything out!

p.s. Please dumb what ever advice down and be as specific as you can. Im not to engine savy.
thanx