How much power? You can upgrade the OD section of an 42 or 44 to 46, 47 or 48 OD internals. But, the OD on an RE/RH transmission costs a lot of power, and increasing pinion and clutch count requires careful consideration based on what you're trying to accomplish.
The front portion of that transmission you're stuck with the smaller input assembly and intermediate shaft, which will be your weak link with more power or forced induction.