I am putting together a 360 and need water pump advise. I currnetly have a new aluminum water pump. That problem is that the timing cover is from a 318 with iron pump. When I put the w/p on, the pulleys are way off. I put the old iron pump on and it all lines up. So, I need to get a new iron pump. Do I want 1 for a/c or no? Does it make a difference? Crank pulley o/d is 6.25 and the w/p pulley o/d is 6.5. This will allow the 318 timming tab to be used, but what about the marks on the balancer? What needs to be done there? All help is appreciated.