the carb i was running has 76-76 jets and pv plugs im gonna swap to another 850 i have maybe ill try your combo 88 squared 3.5-4.5 pv ,do you run that combo in a similar set up to mine, converter doesnt have much stall but doesnt seem to slip i had it rebuilt, its a good billet front unit with a anti ballooning plate and a good stater bearing i think its called.she runs like a bat out of hell for 900 ft then yes the surge and i played with the fuel pressure fom 5.5 - 8.5 psi, converter is 9.5 im sure a big dollar 8 inch would help maybe next year.