1976 C65 Grain truck with 366

[cram]

Ok, I am needing some help, opinions or whatever ya got!
I have a 76 Chevy C65 grain truck with a 366. I have put in a new electric fuel pump after the original went bad. I have also replaced the fuel filter as the o-ring gasket was cracked & in bad shape. She will NOT stay running or get up to normal speed. It seems the more that I fix or replace, the worse it is getting. I am no mechanic by any means, but the guys at NAPA have been helping where they can, but I guess any suggestions would be great.
Thanks a bunch.

[Michaelnevells]

We'll, sounds tricky. Check if it's fresh gas first and take the carb off n clean it out. Some of the jets could be stuck or plugged if it sat for awhile. Might help might not.