1979 Quadravan Transmission Upgrade

I have a Quadravan on a Ford E350 conversion Van, 460 gas,4WD.Question:  I am converting a 21' R.V. to 4-wheel drive using a Quadravan conversion with probably a "205" transfer case and with a adapter plate if needed, I would like to use a ZF 6-speed transmission if it will handle the torque. I know the H.P. will be right around 740 and probably similar torque. Someone told me this would be a good choice. I don't know anything about them? Maybe do your gear hardening on 1st, 2nd, and 3rd?   I need gear ratio choices, and keep in mind the rig weighs about 11,000 pounds.  I will run 29" tires and a 410 rear which will help.Answer:  Unfortunately there isn’t a way to adapt the ZF 6 speed to a 460 gas block application…We can do it with a 5 speed ZF transmission rebuilt, dyno tested and to strength we will cryo treat the input, cluster, 3rd gear and 5th gear this trans would bolt up and be adequate for your application.We can supply it in a 4x4 application with a shift stub and cryo treated gears  your cost is $2400.00 outright, no core required plus freight.Give Scott a call toll free 888-824-2012 he can help you.  See other parts we can provide for the Ford ZF transmission on our site