Cool. Sounds like a straight forward swap. Are there any computer upgrades with the 98 compared to the 95 or they all the same...
1994 Rangers were the last year of the EEC-IV OBD 1 computer
1995 Rangers had the first EEC-V OBD 2 computer....BUT, these were 1st generation OBD 2 so not all scanners can connect with them.
1996 and up Rangers have the current OBD 2 protocol so any OBD 2 scanner can "talk" with them.
The Computers are the same in '95 and up Rangers just the communications protocol is different in '95, so one is not "better" than the other as far as engine operation.
Just stick with the '95 computer.
Computers have fixed firmware for engine size and transmission type, so you have to match those when swapping computers.
There were also changes in sensor types over the years with EEC-V systems.
Cam position sensors were changed from 3 wire to 2 wire, these are not interchangeable.
MAF sensors changed from 4 wire to 6 wire, intake air temp was added to MAF sensor.
But if you swap just the block and heads, the engine parts, then it will be a simpler install as all the '95 wiring will be plug 'n play to the '95 intake sensors.
The only other part you will need to buy would be a flywheel for '98 4.0l as the '95 flywheel won't bolt to '98 crankshaft