The Gentleman's Roadster, Bismarck Build: Dash finished

[dbo_texas]

So this is what I started with. I ground it down so it would have a chance of fitting in the hole of the hydroboost. The blue mark is 1.1”, or the minimum it is supposed to travel to bottom out the tandem master cylinder. Right now I’m at about 3/4 - 7/8”. That’s the full travel of my pedal. The only way to get more travel is to mount the clevis fork lower on the pedal.

IMG_4944.jpgIMG_4940.jpg

I'm not 100% sure i follow, but just comparing where I started (my thread post #104) to where I finished (my thread poste #108), your setup sure looks like my #104 post. I had to shorten the threads on the welded bolt so that I could screw the rod into the cleavis more (otherwise it would hit the back of the pedal arm. This allowed the piston to fully extend to its resting position. From my pics you can see that puts the head of the welded bolt just behind the cleavis...I couldn't even fit a standard nut in there to lock it in place, I had to grind it down to about 2mm thick so it would fit. You may be in a similar situation?
If your piston is pre-loaded (i.e. not in its resting position), that would explain why you aren't getting full pedal travel. I guess the part I don't get is that you say you have clearance to the 3/4 frame already? If so, then maybe your piston is all the way extended towards the pedal (and isn't pre-loaded). In my case, the pedal arm was pushing ON the frame rail initially and the piston was compressed by quite a bit (thus reducing travel and essentially having the brakes "always on").

It's worth noting we have different master cylinders mounted on the front of the hydroboost, so that could explain the differences in our setups. I think my master cylinder is from 2014 Mustang. I was never able to fully determine what model master cylinder I have but just Google searching, that's what I think I have.