[Llay R. Rac]

I have found a few NOS correct number parts for my suburban.
Is there anything to look out for when using NOS parts? I am aware a NOS carb would probably need at least new gaskets, but would something like a water pump, distibutor need new seals? or maybe new bearings? What about things like gaskets , weatherstripping? would anything rubber or plastic still be in usable condition?

I like my truck the way GM made it and am trying to keep it "original style", i am not that concerned about correct numbers, original style works for me and my budget. But if a NOS part is not much more then a repo, why not get it?