Geees worked on a few of them in my time , must say those rocker covers never stayed that green for long , as i remember used to be green with black stripes (smears )
My first car was a Minor Traveller with a 1098 A series. Thrashed the nuts off it all the time. I was so used to working on it I once changed the cylinder head gasket in 50 mins. I couldn't do that on a 4200!