can anyone tell me what type of tranny i can use? i have a 400 and am not too sure what to use. i know that a c6will work but what type of bellhousing am i looking for? would one bolted to a 390 work? is there an overdrive tranny that i can use ? help and suggestions would be great.
The 400/351m uses the same bell pattern as the 429/460. A 390 (FE series) will not fit, nor will any other series bell.
A C6 from one of those engines will work. For a OD trans, you are stuck with the E4OD (requires a stand-alone controller, $500) unless you buy an expensive adaptor for an AOD or Chev trans. ($800+/-) And those transmissions need to be beefed to take the power and weight of your combination.
You trying to get better mpg or just reduce rpm on the highway? And what vehicle, gears & tires?
There are Factory Bell-housing out there for manual transmissions,also a Scatter shield for a 429/460 will work. . There is a nice 3 speed with an O/D that was used in the mid 80's F-150. It is a B&W top loader and the toploader plate has been replaced with the shifter. I had one of these in my street rod project and it's a nice unit. They only run around a$100 to $150 in the junk yard.
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.