Can anyone check 3/4 ton disc brake line size for me?

[davepl]

I'm converting a '70 Longhorn over to '72 discs (also 3/4 ton).

I need to know if the factory changed from 3/16 front hard line to 1/4 when they went to disc brakes in the front. I just can't find anything that says anything either way.

I ordered a repro front brake line kit but even though it's sold as 3/4 ton it's clearly for a 1/2 ton and useless to me, let alone to use as an indication of what is "right".

Anyone have a 3/4 ton and a pair of calipers? I'm looking for the diameter of the hard line between the prop valve and the T fitting (the part that goes down to the frame). If you're ambitious it'd be good to know the diameter between the T and the flex hoses too.

Although many argue that tube diameter doesn't really have much if any effect, especially on short runs, I'd like to do this once and do it right. On the other hand I don't want to redo all of that damned stainless if 3/16 is already right for it!

Thanks,
Dave