Converting Jacuzzi Magnum fixed pool pump motor with variable speed motor

Can I replace the fixed speed AO Smith 1HP motor with the following (see picture below) with an

A.O. Smith V-Green 1.65 HP Round Flange 56J Variable Speed Motor - ECM16CU - INYOPools.com

Yes, you could use the ECM16CU variable speed motor. We’d also recommend the tune-up kit, GOKIT14.