340Help!!

The only thing I see wrong with the combo is the carb is too big. A 650 is plenty and will most likely give better low speed drivability. That cam isn't all that big. Like the others mentioned verify the cam is indeed wiped and as Bill said if it is you need to disassemble the entire engine and clean all the metal flakes out.

BTW: Did you recurve the distributor advance for a quicker advance and less initial timing when you did it? If not you should have as that'll help low end response. If your Mopar ignition is working correctly you'll see very little difference switching to a MSD.