I am dropping a 258-6 into my Wagoneer. The 360 that came out used a 3 groove pulley on the water pum and I want to keep the same set up. I have made custom brackets to hand everything but can't locate a three groove pulley that will work. The 8 cylinder uses a larger diameter pulley and can't be used. The 258 pulley is 5 5/8" in diameter. Any help out there?