The original piece had the pipe thread, 2 or 3 inches of straight pipe, then the nipple.Georgia69 said:
Maybe just put the hose on a 3" hardware store pipe?
On the subject of short water pump brackets, if you have accessory holes in the front of your heads, the alternator bracket for a late 70's thru-82 vette works GREAT! There are 2, one cast iron, one alluminum, the alluminum one will take a polish pretty well. They can be found at corvettecentral.com, or if you can dig up the part # gmpartsdirect has em for half as much.