Check with your NAPA dealer about having them order parts in that they don't normally stock just for you to sample. They may say NO because the parts are no longer stocked at their main warehouse (free shipping for them on a almost daily basis) and they have to pay to have then shipped direct from the manufacturer at your cost.
My parts book has the following Hydrovac info;
1966 Ser. 60 w/ H.D. Brake Booster (exc. TDM., 4 cyc. Diesel)...(Bendix 2503139)....3880384.
1966 Ser. 50-60 (exc. 4 cyc. Diesel, H. D. Brake Booster)...(Bendix 2503151)....3882288.
So it looks like you'll need to know if you have HD Brake Booster or not.
Don't forget to get enough brake line (size???) to do the clutch line as well and get a new clutch Slave Cylinder (Chevy p/n 5460668 (7-25/32" O.L.).
Mike B
