First, currently my car is running FULL RICH (think the MC Solenoid is burnt out of the carb). It's a 350 (getting around 17-19 mph highway) with all the LG4 provisions (computer, carb, dist., and headers and 3" exhaust). Supposing it was running with the right mixture, what kind of performance enhancement am I going to see (in percentage or hp). I'm working on getting this problem fixed. The 350 just doesnt seem to have the power it should for having a descent cam and headers and exhaust and it doesnt feel very responsive. Feels like the 305 basically.

Also, supposing its running full rich, would it be backfiring from unburnt gas in the exhaust? While sitting there idling when its warmed up, it will idle kind of rough, with the RPMs jumping around a little bit by about 100 RPM and it will kind of 'cut out'. If you listen to it idle when its like this it will sound like it misses every so often (once every 1 or 2 secondes). I was thinking maybe it was just small backfires from running very very rich, does this sound like a good explanation. I've rulled out ignition because it has new plugs, wires and distributor cap and a fairly new coil.

-Ben