I dont think the reg rotation water pump will work on the Vortec block...? The bypass on the passenger side is not used on those blocks because of the reverse rotation water flow does not require it...? The reg rotation water pump used this to keep the flow going to the back cylinders and a late Vortec block does not have this hole...
I might be wrong on this but I`m not 100% sure... Although you could tap off the rear intake water crossover and pipe it back into the pump to get proprer circulation possibly...?
Does anyone have link to water flow in a SBC possibly also a BBC...?