1 US gallon is 3.7854 litres, & one Imperial gallon is 4.54609 litres so you can do the math from there.
As a rough conversion, the Imperial gallon is 20% larger, so add 20% to the mileage figure to get a conversion to what we would see over here.

Those weights are interesting. Why would North American B310's weigh in at 772 lbs [350kg] MORE than other B310's? I mean, that's a LOT of extra weight.

This would mean that a North American B310 two door Sedan with A14 comes in at 2,680 lbs or 1.215 KG. Thats almost a ton & a quarter.

If that was true, & I have my doubts, the B10 two door Sedan comes in with a weight saving of 590kg or 1,301 lbs.
I think that something is amiss here.