The INSANE Story About Muir-Hill Tractors | The Downfall 

I noticed that there was a picture of the XO121 Oliver. Did it come from a web search "containing 121"?

not quite sure what northrop tractors have to do with northrop grumman (0.25) Thought they were a Lancashire firm

In the early to mid 70s a rice farmer in our area had one I think it was powered by an 8 cylinder Perkins engine it was a beast 4 wheel drive and cab