I'm not sure of the exact rating of the stock pump, but if you're running a carb instead of EFI (I assume so because of the reference to floats in your post) you only want about 5-7 PSI max. 85 and 125 psi are way high for a carbed engine, and even a bit high for a stock street-driven EFI engine. The important figure here is the GPM rating, of which I would guess you'd be good with about 70 GPM. This is easily doable with an aftermarket inline pump, but the good ones aren't cheap. Take a look at someplace like Summit for a good variety of pumps and their specifications.