Those capacities were US gallons, I guess. Are they used anywhere else in the world? By the time you allow for the fact that a "proper" gallon was the imperial gallon and even when that was in use, it was far more wide spread than the US gallon and the fact that pretty near all of the rest of the world is now metric, it appears to me that you guys might be the only people using the old system. Just wondering.
BTW, 10 US gallons is 37.85 litres. I have put 42 litres in my '29 in one fill. Go figure!
Maybe I was close to walking!