Welcome aboard 68bbccamaro, sounds like a cool build. If the carbs were leaking, then you'd be way ahead if you put a kit in each. Easy to do and will save your new project from possibly becoming a slice of toasted chevy!

The oil?? you "could" probably get away with it.. but why? even if you used a new "inexpensive" oil.. at least drain it into a clean container and make sure there isn't any water or debris in it! Dump the filter also!

My 2 cents - FWIW.. yada yada yada.. ymmv.. rofl..