Replacement radiator source

[OUbesto]

Any recommendations where to buy quality replacement rad for ‘70 C10, 402, HT 400, A/C? Prefer American made. What specs etc do I need to know to order correct replacement model? I also notice there are transmission lines in/out of my current set up. I believe current rad appears to be original. It does have an overflow plastic container that is mounted on the drivers side Near the front inner fender.

Any threads to remove and replacement instructions would be greatly appreciated.

Thanks to all!