The water pump manufacturer should be able to tell you the recommended RPM and you can do the math from there. If you spin it too fast it will cavitate. High flow water pumps generally want to spin slower. On my 292 I used a FlowKooler high flow water pump that can spin 5000 RPM without cavitating. I altered it for the A/N fittings and smoothed the casting. I have a custom made damper with an 8 rib pulley on it. My water pump pulley started it's life as a reverse rotation Ford pulley and I cut the grooves in it and redeemed it. I bought a spacer and cut it down as required. I countersunk the bolts because it's close to the blower belt. For some reason I felt the need to fill up all the holes. Then off to powder coating ($20). Keep in mind to allow .004" to .005" for the powder coating. I realize most people aren't as crazy as me but the principles are the same. Thank you for your time.
