I'm in the process of assembling my small block stroker. Had originally planned to just re-use the water pump off my stock 340, but after seeing how crusty it is, I'm going to spring for a new one.

Not looking for anything super high performance, but I want to make sure I get one that will move enough water to keep things cool with the extra power that will be on tap.

Rock Auto lists about 10 different pumps; some with six vanes, some with eight, some with A/C, and some without. Other than impeller design, are there any differences?