You are fortunate in having parts buses. When I looked for a gear box, I knew where there were several scrap 4501s and they were all missing the fan box.
So why doesn't someone just take the RPM reading of one of your squirrel cage fans when your engine is at peak RPM, and then remove the drive to the fan and put a big DC motor on it, run it up and measure the voltage/current (ie horsepower) it takes to duplicate that measured RPM. In a nutshell all the arguements would become clear as to whether it will or will not work... Maybe we can all place bets...