Pool is 18x36 vinyl oval
-one skimmer and one main drain
-two returns in shallow ind
-All piping 1-1/2 inch plastic
-pump located about 40 feet from pool inlets

Filter:
3.1 SF sand rated at 4.7 to 6.1 GPS at 50 PSI

I can't find a pump curve for the dead ITT Marlow pump - but I figured out from part numbers on the impeller that it is a 1 HP. I'm only guessing a modern 3/4 HP will be sufficient without overpowering the filter