e4od tranny option not cheap. Hughes trannys offers a manual shift version of this tranny, not cheap but no computors for the 400. another option is a ZF-42 5speed BUT their are some issues when doing this. if 4wd shift rods need to be clearanced on rear flange and need to run a thicker flywheel. possible to run a 460 flywheel and build a shim to center on back of 400 ford and holes need to be drilled. or have flywheel custom build, not cheap. i have many photos of zf conversion for a 4wd if curious. check albums. the splines on clutch input shaft are only about .250 on shaft at most and a questionable durability situation. can be run but if stout engine will probably be a issue down the road. check photos and drop a message if needing help.