The car had power brakes when I got it and those are the lines (I think they are original) that were on it then so they did work with the original master. If you look at the pictures, I think one of the lines would work for MC to proportioning valve, but one is way to short and looks like it would go into the top of the proportioning valve rather than the side as shown in the comparison pic of the old and new lines. So the problem I have is one line from the MC to proportioning valve and the fittings from the front brake lines and the rear brake lines are incorrect that go from the proportioning valve to the wheels. That would not be affected by what master I use.

When I converted my 65 Cuda to discs I used the same style MC you have, no original or stock for either of our rides. I used the brake lines and prop valve off a Diplomat and tweaked the lines to fit. Which is probably similar to what whomever did your swap did.

You probably ordered stock lines for your vehicle, which as you found out are not even close to being what you need.