Bill, the most important tool you need for this(or any) swap is your tapemeasure. A couple here are the overall width from wheel mount flange to wheel mount flange, the torque tube length, and center to center distance on the spring perch holes. If you leave the present springs in the 40 a different spring length isn't a problem. Every problem is fairly straight up, like standard bellhousing crossmember will probably have to go, and shift linkage fabricated but, if the torque tube is way different in length, then some involved work might be needed. Others will chime in and point out other potential head scratchers. Good luck

Evan