1983 Plymouth Scamp GT - Lacking in Performance

Sounds like a fuel issue to me, I've seen this before, on my own '83 Scamp GT.

A few things to check, first is the fuel filter (Bypass style Return Fuel Filter), it may be falling apart inside and returning too much fuel back to the tank. Do Not Replace it with a regular 2 Port (In/Out) Fuel Filter.

Second is the Fuel Pump, test the pressure and flow. I can't remember the numbers anymore, but I'll check my FSM when I get a chance, and I'll let you know.

Third is the Rubber Hoses that connect the Steel Lines to the Tank, Pump, Filter and Carb. They may be collapsing partially or completely and starving it for fuel (I've seen this happen a lot, even on brand new rubber fuel hoses)

Fourth is the god awful nightmarish "Hoggey" (Holley) Progressive 2BBL Carb that was used on the factory 2.2L's. Most 2.2L Owners smash em with a BFH and throw em in the scrap pile, before bolting on a Weber 32/36 Carb. I've even seen some where people have bolted on 4 Mikuni Side Draft (Motorcycle) Carbs. but that's getting into some custom work, where the Weber bolts on with the supplied adapter kit.