Yes,Craig, the brass junction blocks would have to be changed. The tube nuts are larger on 1/4" lines than 3/16". My 50 has all 1/4" lines while my 51 is all 3/16" except for the main line from the master which is 1/4". I believe this was because of the change in brake systems from 50 to 51. Along with going from the Huck brakes to the Bendix, they also changed the master cylinder,1" bore in 50 to 1-1/8" bore in 51.
Weren't you changing your front brakes to Bendix also? I would run all the same line, but I'm not sure if it would be better to go all 3/16" or 1/4". If your master cyl. is a 50 it should be a 1" bore.
