What year did the bypass hose size change?

So my intake is a '69...water pumps are later.


Since there isn't any way to change the as-cast larger water pump fitting I have to figger out how to adapt/reduce/enlarge the intake to fit the later bypass hose fitting.

Maybe just fitting an early water pump to the engine would be simpler because the lower hose is a larger 1 3/4" too!

I was going to have the rad lower inlet moved to the passenger side to accommodate the newer pump...buying a an early pump would be so much easier...BUT

There's the other issue I may have screwed up... I think I bolted on a harmonic balancer for an internal balanced engine...this is a late '73 built engine with a cast crank. Timing cover is a later deal with the marks on the left. If I use an early water pump the cover is wrong...geez....