360 Rebuild for 1974 Swinger

The end play is controlled by the retaining plate. Just slide the cam forward, and if you have to wedge a pry bar behind one of the cam bearing journals...
eyeball line up the keyway and slip the gear on the cam, then use the rounded washer and bolt to pull the gear on the rest of the way. That is by design a tight fit. So you can pull it on or use the oven to expand it and then try again. Don’t hammer it, and don’t file it to make it fit more loose.