Or just get a 5 speed one thing you should be aware of though is the nv4500 has been known to have the 5th gear ring nut back off and you loose 5th gear. It is caused by lugging the truck in 5th gear. It can be fixed 3 ways 1st ring nut retainer clip 2nd you can weld the nut to your input shaft this is the best way if you plan on building the tranny later on 3rd get all new billet interals and have a bullet proof tranny