I can completely sympathize with what you are going through. Had the same problems with my Rochester B. In fact, I rebuilt two of them (bought three to get enough parts as they are cheap), but I only rebuilt them four times, not five like you...
Still had the same symptoms you described, though maybe a little less severe.
The last straw for me was on the final rebuild, went for a test drive and the truck died at a (thankfully) rural intersection. Would not restart. But when I looked in the engine bay, the Rochester was pouring fuel out of the accelerator link hole, all over my hot exhaust. Scared me to death. Standing there on the side of the road, fire extinguisher in hand, and waiting for my investment of a years' worth of time to go up in flames, I decided that $125 for a professionally rebuilt carb would be a good investment.
Sent away to a company in CA and swapped out my Rochester for a shiny Carter YF 2100S.
Have not had a lick of Carb trouble since.
I know it's not where you want to go, but it's worth considering.
Best of Luck,
Jim
