My suggestion for you, moving forward, is to try to buy OEM used parts whenever you can. They fit better, and putting vintage US made parts on your vintage truck will make you and the truck feel "right".
If you don't have any local access via salvage yards, etc. try these fellas:
Tony Smith:
http://4-5-6chevytrucks.com/Rich Sisneros:
[email protected] 1-719-267-4604 -or- 1-719-250-5057
Good luck to ya!

John