I have a 1943 Chevy Fire Truck with a 216 Engine. I need a new water pump. I have removed the old one and found that it has a 3/4" pulley. I'm having a super hard time finding one to replace the old. I have found one that is out of stock with no known arrival date. I can also find lots of them with the standard 5/8 pulley. Any help on what I might can do to resolve my problem? The pulley is attached to the water pump so I cant change it?