I'm looking at acquiring a '47 Buick sedanette which I would use to do some long distance touring (month long trips, thousands of miles each). I know the nailhead eights are renown for their reliability, but wonder what kind of gas mileage they get? And are their any routine issues one might expect to encounter in such circumstances that I should be aware of (overheating, vapor lock, etc.)? Thanks for any advice offered.