Stop in for a cup of coffee

Also trying to confirm the two heater hoses for the 67 383 are both 5/8??
That's what I have and someone thought one should be 1/2 inch.
Don't think that change happened until 73??
Ordering a new heater core for it.

I would go with 5/8" for both sides myself whether original or not... The 5/8" will have more flow and more heat for the heater core...