Mid Brunswick Green was a popular colour on Listers unless it was in an industrial set up when they were a Yellow.
I have painted a few engines from stationary, mowers and tractors.
I have used high temp engine enamel and 2pak paint straight onto the bare metal.
On the mower the top of the cylinder and head the paint burns off using high temp engine enamel, same with the exhaust manifold on the tractor using 2pak and stationary engines are great when water cooled but head still burns it and air cooled engines have the same issue as the mower.
Aparently there are some very expensive ceramic coating paints that I think require baking on that will stand up to the job but I have only seen one job painted in that stuff and the engine is not running yet, it has to wait for the restoration of the car first.