Was the Lister 8/1 ever made in an air-cooled version? A local Lister parts dealer told me he saw one the other day and that he had never seen one before.
John
www.gasketstogo.com
The Lister VA is the engine you are thinking of, wrightkiller's picture shows this engine.
The bottom end is basically the same as the water-cooled 8/1 but the cylinder, head, rocker cover and the flywheels etc are all different.
Made for the Middle East market by Lister, it had a reasonable production run. We had a couple through our hands over the years.
Peter