[DirtyLarry]

Not all 73-87 hydroboosters are the same. The difference is 1981 and newer hydroboosters have metric fittings (M16 & M18) whereas the older ones had standard fittings (3/8 & 7/16). This is not a problem if you also have a steering gear with matching fittings otherwise you will be either having custom hoses made or replacing the steering gear to match the hydroboost hose ends.

I would not recommend using your old master cylinder. If I remember correctly, my old vacuum m/c wouldn’t even fit the hydroboost unit. Another thing on my truck was that I had to swap the brake line positions at the m/c as the front and rear ports are reversed on the larger m/c vs. the small m/c’s.

Yes, your current P/S pump will work. You can just add a T fitting to tie all of the return hoses together. G-Gans, and P-chassis were plumbed this way whereas the trucks had a dual return ports in the p/s pump. In my signature there is a hyperlink to my NV4500 swap. In that thread is some information on hydrboost as I converted to it while the truck was under the knife for the trans swap.

Regardless, $80 is a great deal for what all he is offering. Go for it! I love my hydroboost and plan on swapping one my Suburban soon as well.