There is no special numbers for castings. The intake from a 91-95 4.0L wrangler or Cherokee and all the wiring from under the hood because they are very similar. No Grands because the ECU and wiring are different. Everything is pretty much bolt on. The ECU needs a crank position sensor input and a Vehicle Speed sensor input. So you need a Flywheel from a FI or the Hesco cranks setup and a VSS that combines the mechanical cable with a electronic output like the 91YJ. Last is the fuel. The MPFI have a closed loop system with high pressure pump in the tank. You can get a used tank and pump setup for around $100(It gives you an extra 5 gallons) and replumb the gas or get an external one that is self regulating.
You can do it on the cheap and I think for under $500 be MPFI.
The head swap is something different and not needed for the MPFI. It suppose to give you an extra 40HP.