Your old stock fuel pump will work just fine. The fuel pressure output is going to be the same. If you are upgrading the motor to an H.O. the differences are the head (valve size), exh./int. ports are larger on the H.O., throttle body size, fuel injectors are larger. Because this stuff is bigger it really means more EFFIECENCY and some power increase. If I were doing an H.O. upgrade just do the head assembly, int./exh. manifolds, and all the stuff that goes on the int. manifold...i.e. throttle body, injectors, fuel rail, just to be certain it all matches up. But to also verify that just cross reference the "old" gaskets to the "new" gaskets from your current Jeep to the donor. Hope this helps.