Only 4 cylinders working

SOURCE: transmission vac lines

A mild cam should be ok as long as less than 220degrees duration (at that point it starts messing with engine vacuum at idle... that's where downshift problems begin) The trans kit does concern me. A tiny piece of dirt, or anything else can mess with the valve body. Generally the kit will just firm up your shifts, and should not change operation overall (unless you got a manual valve body kit, in which you are required to manually shift each gear (up and down!) I'd mess with the modulator some more and maybe even linkage adjustment.
Good luck

SOURCE: Popping Noise from unburned fuel in carb - 600 edelbrock manual

try a smaller more factory carb.and see if it helps

SOURCE: MISS FIRE

i have a 355 motor and i run autolite copper plugs and they work great, and most plugs are pregapped but just as a refrence 0.35 thousandths is the gap for that

SOURCE: 1979 chevy pickup, sometimes stumbles went through

Check for a weak fuel pump or loose ground wire.

SOURCE: I am going from a qudrajet carb to an Edelbrock

If your staying with the stock intake manifold the edelbrock wont fit unless you install a adapter plate.And i would advise you not to install it will not seal properly.I would install a edelbrock intake manifold and carburetor as a matched set.You can purchase a edelbrock carburetor and intake manifold from advance auto parts that's designed for your vehicle.