OD of heater hoses '87 Caprice?

I need to order some hose coupler's and if somebody happens to know the OD of the heater hoses let me know please. Then I can order them online here and get them before the holiday weekend. New stuff small and big going into this thing everyweekend. Can't wait 'til I'm 100% happy with the engine compartment.


http://i121.photobucket.com/albums/o219/ernestmayhand/Caprice%20resto/_DSC0006.jpg

Depends on what hoses you are running. Use a caliper.

They're sized by ID, not OD. The ID is 1/2" and 5/8".

The ID is 1/2" and 5/8".

I'm going to install a ball valve to prevent coolant from going into the heater core in the summer. Don't have the motivation to fix the vacuum actuated valve that comes on this car at the moment. Which is the inlet and which is the outlet on the heater core? I've got the 5/8" going to my radiator (upper right) and the the 1/2" goes to my intake manifold. I'm guessing the 5/8" is the heater core outlet? I'm running a serpentine setup.

Yes, the 5/8 line is the return.

No luck at the hardware store because I guess 5/8" doesn't exist in the plumbing world. Got to find something at an auto parts store (even though the first auto store I called told me nope, check the hardware store).