Well.... without being there to tinker with it it's hard to say. Usually where I start first on the fuel system is the pump, make sure It is pumping the correct pressure and getting volume. You said you had garbage in the carb? Is there a fuel filter after the fuel pump? I had a carb I had terrible issues with first of all stemming from a new mechanical fuel pump I put on that was putting out too much pressure and flooding the carb, have had float issues, and have also had fuel pumps with bad diaphragms... Then there is the all of the fun Holley carb adjustments that can be done with some google searches, i involves some tools, black magic and timing tuning as well. I know you have a lot of time invested in that carb, but sometimes bolting on a new one is a cheap and easy way out in the end. All of that being said if fuel delivery is wrong and your pumping junk into the carb none of that other stuff matters. Just my 2 cents.