For the guy that needs master cyl mount info

[dicer]

On the left front cab mount the forward mount to frame rivet center line
is inline with the pedal arm pivot point in the for and aft direction.

The rear master cylinder bolt is 1/16 behind the rear master cylinder to frame bracket rivet center line. Looks like master cyl bolt holes are spaced
2 3/8 apart. You should have existing rivet holes in the frame to go by.
The down from top of frame rail to bolt centers 2 3/8. There is a picture from the assembly manual someone posted on another thread here about 56 master cylinder that may help. I could not find your original post. Good luck.