360 performance help

well you should check the fuel pump make sure it's got pressure. You should I have a friend rev It Up with one of the plugs wires pulled loose real quick and see if you get spark over that RPM that way you'll know if that GM module is bad. Lastly I guess would be the springs... in order of what's easiest to check.
The Springs should be around a 115 psi seat @1.7 or something like that. There might be 2 versions. I had a set that was 140 seat 471 rate long ago, still have the box.
If you have the 115 seat.. ugh I'd put them in at 1.68/ to get a decent 120-125