Conversion kit? yup, Mopar Performance sells a complete kit to go from a carb 258 to f/1 that is based off a 95 jeep 4.0 set up. Problem is, it's uber expensive. What all did you get, just the engine and trans, or did you get the wiring harnesses as well, along with computers? If not, you may want to pick up a rotted and blown up cherokee for parts (no joke). There have been a few members that have pieced it together via junkyard runs, but, it would be far easier, and cheaper to have a complete vehicle to take parts off of. As far as the swap, can't help ya there, haven't done it yet, lol.
Oh, the best pump would be the factory one, depending on the year 4.0, fuel pressure was regulated at the pump or on the rail. If you have a rail regulated one, just use a pump that has the same or similar output of what the factory jeep one did.