You can get a motor that has 4 posts with 2 of them being the same center to center as the Moroso 2 post motor but is a more powerful permanent magnet motor from W. L. Walker 918-583-3109 or wlwalker.com
The part number is 18051. This is the company I work for. We sell stuff to test measure or sample oil but I used this motor on a few friend's water pump and they run much faster also. Depending on the input voltage they will run 2100-2250 rpm. It has the same 5/16" shaft. Just grind down the 2 posts that you don't need. Just an option to consider. Looks like they are about $11 more than the Moroso motor.
Curtis