I know his carb -- I know it pretty darn well and it should be plenty, if it isn't broken and there's nothing else wrong. Out of the box, it's 750 CFM, the primary jets are 70, his secondary metering plate (not a block) is 21, which is pretty much the same as 75 jets, it came with a .031 nozzle, and a 6.5 power valve. I have the same carb and it serves me quite well.
It's either broken, or the problem is elsewhere....