What year did the bypass hose size change?

If using the 70 up aluminum water pump with an intake that has the 69 and earlier smaller bypass hose fitting you have to use a 1" hose barb X 1/2" MPT fitting. You will have to use a brass fitting-the only thing that i have found. I like the clamp style that is smooth with a bead on the end. There is a place that used to have these but they have been discontinued. So the only ones that are available are the barbed type. When I use one of these I grind the end rib off to shorten the fitting, otherwise they are a little long. You can get them at fittingsandadapters.com, part number MPT-16-8 at 7.36 each. Home Depot says they have them, you can check and I found them on Ebay-auction number 185247657448 at 10.48 each. Again 1" hose barb X 1/2" MPT. I like using brass fittings on aluminum intakes-they don't rust and you can remove them easier if need be.