Brakes "skip" as I press down. Whats goin on?

X2 on the '67 and later dual reservoir master cylinder. You'll need the correct dual res. distribution block also. That is the brass chunk mounted on the frame rail where the brake lines from the master cylinder go, and where the front and rear lines go to their respective wheel cylinders. The '67/up block has two ports for the master cylinder lines. This is an excellent upgrade!