What is enough vacuum for power brakes?

I looked at those links and the biggest detail isn’t given, and that the bore diameter of the master cylinder. It should be 15/16 or if you like a bit firmer pedal feel 1 inch. I’ve never gone bigger than 1 inch.

The other thing is you need a different pushrod. Other than the new MC and pushrod it’s pretty much a bolt on deal.

Thanks for the info. I would have to replace or cut/fab brake lines to fit also. With the first engine/cam I went from Manual to Power brakes so I think I have the original manual pushrod in my stash of parts somewhere gonna go out and look.