You should be OK with a stock volume pump to cool an SBF sometimes higher volume can actually move the water too fast if you have a smaller cooling system which does not allow enough time in the radiator to take advantage of cooling.I would turn the Autozone pump in for warranty unless it is off shore made.Was it the $59.99 unit?
Hey tapkoote, Nice car, but it's a Styleline, not a Fleetline. The Fleetline was a "fastback" body style. It's good that you've got updated brakes. Parts for the original 49-50 Chevy brakes are impossible to find.