odd carb thing
 

ok working on a base ass 84 12a with a/c and thats it not even a map light. any way to the question. just slaped a newer motor in this 84 and she idles and revs GREAT but under a load when you floor it it shits... starts jerking, wont rev, loses rpms and will die. now if i just add a little gas at a time and dont floor it she does fine and will rev up to 6-6500( dont want to rev new motor to high yet) but as soon as i stomp on it , it craps out again... HELP

Try adjusting the accelerator pump and see what happens.
hanman

Check your cap and rotor for corrosion. Had a car do it on me. Idle fine rev fine put in gear and unless I took off slow it die. Turned out to be corroded dist. cap contacts

i cleaned the button the cap looked fine didnt help any

or a carb rebuild maybe in order

carb had a rebuild less than a year ago