Yes kaase p-38 heads bolt on to the short block but it is NOT a direct fit The short block's pistons are notched for Windsor heads. Kaase p-38 heads are Canted Valve like Cleveland heads. Your options are 1. Notching your pistons, but you will remove the thermal coating on your Mahle pistons and the balance will not be true 2. Mahle also makes pistons for Kaase p-38 heads maybe the engine builders that work with frpp can be convinced to install p-38 specific pistons instead of Windsor pistons 3. Have your engine builder install p-38 specific pistons and balance the assembly
Those heads will work well on this shortblock. They do offer some variations on their heads so I would provide them with the specs of this shortblock to determine the best combo, but they will work on this application.