Note: Sorry I can't give proper credit, but I can't locate the fairly recent thread re: MC replacement options, in which a poster determined that, with boosters removed, a 3/8" reduction in the brake fulcrum arm length would have the same impact on pedal pressure as going with the "popular" option of procuring and re-piping a Spitfire or similar .7" bore MC. Not sure if anyone actually tried this, but, because I was about to sell my car (boosters bypassed, original MC) I felt it was worth a shot. (I had almost gotten used to the super hard, non-boosted pedal pressure, but didn't think a new owner or test driver would be pleased.)
Happy to report that it worked like a charm! The car is gone, but for posterity sake, here is how the project went:
I measured down 3/8 from the existing pivot hole and drilled another one. Easy.
You next need to raise the whole pedal base by 3/8" to line up the new hole with the MC push rod clevis.
As a prototype, I built a stack of 1/8" X 2" aluminum stock from Lowes. This gave the proper lift, but did not support the entire width of the base, which is 2.5". But close enough for proof of concept. For the final version, I had a local metal shop cut a 5.5" x 2.5" piece of 3/8 plate. Also can be found on line, e.g.:
https://www.ebay.com/itm/353419004742 Then drilled 4 holes for the mounting bolts.
And here is the rub: The OE pedal assy attaches with welded studs that can no longer reach with the spacer in place. The answer is to cut off the studs and the drill and tap the bolt head that was part of the stud. This allows any length of bolts to be inserted from the bottom. (Note: Luckily, I did not have to do this since the replacement pedal assy I bought earlier had, for some reason already been drilled and tapped.)
Then it was just a matter of bolting everything together. No new MC, no brake pipe contortions etc. And a very big improvement in pedal pressure. Firm, as in good old sports car non-assisted brake firm, not as in "OMG I'm going to crash!" firm like before:)
But, there was one catch that I hadn't anticipated. And that involves the forward pedal travel limit rod welded to the hinge. It, too, needs to have 3/8" more underneath it or the pedal sticks way out. So, I had to fabricate another, small spacer and install it.
EDIT: As seen in the photos, I pinned the spacer to the base with 1/8" tension pins in order to make installation easier.
Hope this helps somewhere down the line - and thanks once again to the unsung hero who posited the idea. If someone knows, please add an attribution.
Ron
