True about the slippage with the trans and no low end torque. The lack of spring pressure will also cause the lack of low end torque, detonation and lack of power. Overall poor performance. Poor fuel quality, octane and pressure will cause as well.

3 years is a long time for fuel to sit in a carb, lines and tank. The fuel in the carb likely gummed up internals and or just evaporated completely leaving sediments on the free floating needle and seat and float causing it to stick. Clean lines internally with carb cleaner and blow lines out with compressed air. Replace all fuel filters and would replace fuel pump as well as the diaphragm has likely deteriorated. Free up all internal carb parts.

My revised suggestion is to run 102-110 octane in it and see if there is any performance improvement. If pinging subsides, but performance is still poor, clean the entire fuel system as it seems the first likely source of problem. Replace filters, pump, clean out gas tank. Run car again.

I have an inline filter and a carb filter..One is metal, cadmuim color, GF 98 is the part number. Carb is a paper element with cad colored ends.