If my memory serves me....
the 400's had a short shaft, long shaft and stub shaft for 4x4 transfer case use..... so the short shaft should be good.....that ebrake set up was used on a number of MH's that used the 400 set up....I believe it's the same short output shaft as the standard passenger car/truck set up....
now there is a 375 trans that was in use that used all the turbo 400 internals but used a long output shaft that used a 350 size slip yoke.....but they were only long tailshafts....and were not used in MH chassis.....
not sure If I'm helping things or confusing the issue.....[S