Which conversion are you talking about? If it is the one that uses Mark 7 rotors....basically hub/rotor combos that look just like the stock ones but with 5 lug, then yes you can keep everything else the same.
However, I wouldn't waste my money on those kinds of setups. For starters, you can save yourself a bunch of money by getting those parts locally. Go to your local auto parts store and ask for some 89 Mark 7 front rotors and Ranger rotors, then go to a boneyard and get some Ranger/Aerostar rear axles.
Secondly, those stock style Mark rotors don't support most SN95 wheels. The hub sticks out too far for most SN95 wheels.
Don't waste your money, do some research on these forums, you will find much cheaper and better options than those pre-packaged, overly expensive kits.