Motor upgrade to Variable speed

My current motor is a 1.5hp SP2610X15. It is manufactured by Century, but I believe AO Smith makes the same exact pump. I am looking for a direct replacement, but I want to upgrade to variable speed. I cant find anything online that says any motor will have the correct flange/shaft that I need. Any help will be appeciated.

We do have a variable speed motor for the Hayward Super Pump model SP2610X15. The part number for the VS motor is ECM16CU.

The seal kit is part number GOKIT3. Use GOKIT3SALT if you have salt water.