3 gallon Roadster tank

I just put new petcocks on my 1973 Roadster, put a little bit of gas in, just enough to get me to the gas station a few blocks away, and went to the station and put in..... 2.9 gallons! I'm pretty sure this is the OEM tank, but I thought it was supposed to be a 2.5 gallon tank?.... - BrianK

2.5 UK Galls, which are a bit bigger than US ones.

1 Imperial gallon = 1.20095042 US gallons

Ah! Mystery solved. Thanks folks - BrianK