I have that squirrel cage water pump drive and the motor gave up at the drag strip one day. Actually I was able to spin it and get it going and it worked but no longer kept my confidence...
If you do do an electric water pump you do want to do the reduced drive pulley as not triangulating the belt it will be driving the alternator to fast at high RPMs and the belt flies off... At least that was my experience at the track and what prompted me to get the smaller drive pulley...
Even though I bought a trailer, I could still end up driving it down to the track. The more I think about it, the better I'd be with an underdrive crank pulley and leave the electric water pump to the Drag Race Only guys. I hate overheating issues
