Constant air when bleeding

Ok, no matter how many times I bleed the brakes I am getting air in all 4 corners. Car is a 1968 Dart, factory KH disk car. I did the 8.8 swap for rear disks and 73+ swap for BBP. All new soft lines and calipers on all 4 corners. New 15/16ths master that was bench bled. No visible leaks, no matter how much pressure I put on them. I DO HAVE pedal, but have gone through several quarts of disk brake fluid, and no matter how many times I bleed them (with the buddy) system, I’m still getting significant bubbles on the first two holds. Ideas?