69 340 DART HEATER HOSES

I purchased 69 Dart small block heater hoses from Mancini. It turns out that the kit was for two 5/8" hoses (same thing at Classic Industries). I've read Forums here and it sounds like most 69 Darts had two 5/8" hoses. I don't know if my heater core is original, but one hose is 5/8" and the other is 1/2". Does anybody know of a business that sells these heater hoses with the correct numbers?

Thank you.

The heater core in/out should both be 5/8” as far as I know.

Someone may have switched parts on your car.
They would have had to switch both the heater core and one of the hose fittings.
Longer explanation here Authentic A-body heater hose