Acording to the Rover book of words the Kerb weight of a series 3 109 soft top is 3471 pounds, that includes 5 gallons of fuel. Or 6 and a bit of yours. Max payload with two passengers on the road is 2000 pounds so add the two and you get a gross of 5471. Now comes the fun part ! That makes it roughly 2.5 tons Imperial (Proper tons!) or 2.74 US short tons. At least we agree lbs weigh the same! So nothing should exceed those figures (Theoritically).