Revamped cooling system

Street or strip? Both?
Electric pumps require a revamped charging system- it's a large, constant draw. In addition to the "big electric fan"...
A smallblock water pump will put out about 40 GPM or more, give or take, depending on vanes and pulley ratio. the electric will not substantially change anything but the load on your electrical system. Track cars use them to minimize parasitic losses to the engine.
You made no mention of having a shroud on your current setup. First things first.