What year did the bypass hose size change?

The pulleys are much different between the cast and aluminum water pump too. So is power steering pump.

The newer aluminum water pumps (70 up) are also about 3/4 inch longer than the cast pumps. This can cause radiator clearance issues. I swapped from the old water pump to the 70 up pump. Lots of collateral damage on everything else. Wish I had not done it.