Brake rod for pb, how to set up

[Zappafan]

I've converted over to power brakes by using the parts from my old 71 and putting them on my 72. I've put the different rod in now that I've gone to power brakes and I noticed that the pedal is much closer to the floorboards. In fact it was activating the switch for the brake lights. I've just disconnected it for now. Is there a set length the rod should be or will the pedal come up a bit when I hook up the vacuum line? I don't want to hook up the brake lines and bleed until I'm sure I've got the rod set correct. If I can get the brakes working I can get her on the road and sell the 90.