Acceleration hits a dead wall

On a slant six the eccentric is ground onto the cam as a lobe. If it is worn out the cam needs to be replaced. That said, I would not discount the possibility of a bad replacement fuel pump (even several).A few years ago I ran into this problem on a 318. Multiple bad pumps from several different sources. I did a "band aid" repair, to keep the car usable. About 2 years later I got another pump, and that one was fine. Just had to wait untill all the defective pumps got out of the system.
Back to the original program.
Check the fuel pump pressure, and also the volume. Put the hose from the fuel pump into a container, and crank the engine. The pump should flow at least 1 pint in 30 sec at idle. To check pressure install a "T" fitting between the pump and carb, and connect to a pressure gauge. At idle should have between 3 1/2 and 5 lbs.