1/4 mile times
Try a real converter tci's are crap....
I agree 100%, its your converter, you do not have enough stall period, & TCIs for the most part are crappy, call PTC in Ala., they will put you in the right converter for the right price, you don't need a high $$$ converter for what your doing, just a good quality piece, no need shelling out 9-1000.00 for a converter, thats rediculous, unless your shooting alot of N2o & you need a balloon plate & a special stater, a 500.00 unit is all thats needed, i would get a 38-4200 flash stall.
As for the gears, you have 3.91s, going to 4.11s won't do much, if not anything, so run those.
Your 750 will be fine also, holleys are great carbs, & very tuneable.
Nothing wrong with the .509.