Will a 1968 Ford 302 water pump work on 1977 302?

No, a 1968 Ford 302 water pump will almost certainly not work on a 1977 Ford 302. While the engine displacement is the same, Ford made significant changes to the engine design and accessories over those years. The water pump mounting points, pulley size and configuration, and even the inlet/outlet locations are likely different. You'd need a water pump specifically designed for a 1977 (or very close year) 302.