1991 P30 454 intermittent surging, power loss

You say it bogs down when accelerating at low speeds, what does it do at high speeds? It this problem only at low speed? when engine is hot? Does it run better when engine is cool? Does it run fine once you get above a certain speed? Have you checked the timing yet? Base timing should be 4 degrees BTDC, 454's run better when timing is advanced to 9 degrees. It almost sounds like you're not getting advance when you accelerate if your problem is ignition or you're not getting fuel flow from the fuel pump if it is a fuel issue. Your pressure could be fine but if you don't have the correct flow rate, it can cause hesitation. There is a spec for this, x number of units per min. If you pump is original think about how many gals it had to pump at 8 mpg verses your car at 30 mpg over 58k miles.