Internal Physical Differences Between a Source Four 750 and Source Four 575

The only internal physical differences between a Source Four 750 and a Source Four 575 are an extra hole in the lamp base housing housing assembly which accommodates the 750W lamp key pin, and the paint on the reflector housing. 

The reflector did NOT change. 

There is not a kit to modify a 575w cap to hold a 750w HPL.