LIV1S, I had the same problem, think that was the issue as I have a 72 Pre-L. The extension coupler/stud only cost me 2 dollars at a local fittings retailer, just took me some time to make sure I was doing the right thing and not missing something. It makes sense now if the later cars have some other mechanism to lengthen the adjustment.
Here is a shot showing what I started with. Clearly the pushrod stud was a lot shorter than the stock unit. I probably could have swapped them, but honestly the hex nut coupler and stud method worked well because it made it easier to connect to the piece on the pedal with my finger. As you guys know, there is no room to get your hand up in there and no real room for an open head wrench to turn it, so you have to use your finger to hand tighten.
This shows the 90 degree 1/8" pipe fitting to flare that came with the CNC unit next to the stock flared line/fitting. Not sure how that was ever going to work without an adapter. The picture helped me at the hardware store though to find the 90 degree 1/8" to 5/16" female flare
that did connect to the stock line.
I didn't bench bleed the master, just filled up the master and had my girlfriend pump the clutch slowly initially and then rapidly to get the bubbles out while I kept filling the master and checking the slave to make sure the drain hose on the bleeder was still on and not spraying the passenger side head. Holds pressure and has good pedal movement. Flushed the old fluid out with some leftover Prestone DOT3, then filled it up with Penske DOT3 behind it. I left the stop screw on the slave at the same point, the only thing I might change is the dust boot is extremely squished in the disengaged position which I'm sure will make it wear down quicker, so I will try to pull that further down the pushrod on the slave to give it a more relaxed position.