Having trouble finding a bypass hose fitting for a 68 340 intake. The later ones use the more commonly available 3/4" NPT fitting, but the early manifolds use a 1/2" NPT fitting. Hose ID is 1".

As I recall the early LA's used a 5/8's bypass hose between the intake and water pump. The later ones used a 3/4. could be wrong though. Are you measuring the ID or OD of the hose ?

speedway mtrs has a very nice selection of neckdown hoses/fittings. You might check em out online & likely could cut/trim one to fit your app. Is there a smaller ID 90 deg bend OE type bypass hose avail for the early pump/early intake?

You might be on to something about the hose size. Helping a friend out. He is going from an aftermarket intake that had the 3/4" fitting using the 1" hose to a stock intake with a 1/2" fitting. The water pump uses the 1" hose (ID measurement) that matches the aftermarket intake fitting, so I bet he has the wrong water pump. Dante's doesn't have the right one. Just checked an old 273 intake and it has a 3/4" bypass hose using a 1/2" fitting.