Measuring the speedo against a car with the right sized tyres on shows the speedo is currently reading 17.5% low so thats really 198 miles and 12.4 mpg, a 50% improvement.
Should be even better if its kept down to Motorway speeds and not stuck in a muddy field for an hour revving its pods off :chuckle:
Yeah you should be able to get 14-15 mpg out of that old chevy iron, given a light foot on the pedal and a bit of a tail wind. Now take about 2mpg away by adding Bilko and the food supply. :lol: