Depends on what needs to be done to the 283 for a rebuild. And they are great engines. You can build one that will be leak free if you want. No harder to keep oil leaks from happening with a 283 as there is with a 350.

Just finished up rebuilding a 283 out of a 57 Chevrolet. Runs great and is dry.

Sealing materials are much better now than they were 50 years ago so shouldn't be any problem to keep oil leaks at bay.

The only big question is will it need machine work (block bored and new pistons) or crank turned? But even then shouldn't be a deal breaker.

Nearly everyone wants to suggest a crate 350. But in my experience they really aren't enough cheaper (if any) than rebuilding what you already have into a sweet little engine.