Honestly, if the car was at my house, this is the order I'd start. And go as far as needed to get the ship corrected..... lol
Check that the throttle is truly going wide open. Sometimes a simple throttle cable adjustment (or kickdown linkage binding) can add a whopping 70 hp... LOL.
check that the 4bbls are coming open when the throttle is wide open. Both #1  checks would be done with engine off and in 2 minutes under the hood. That's why that would be the first two things on my list.
Initial timing. A good guessing game would be 15* idle and 35* total. I'd go from there according to what the car liked.
I would suspect by now the car would be doing good things, but if not, I might do a compression test. Make sure something stupid isn't going on with valves sealing, etc.
It's an eddy, spring kit and metering rods are cheap. Richen it up and see how it responds.
Remember, were not looking for 1 mph and .3 tenths. Were looking for 12 mph and 1.5 seconds.