If your lucky and it starts you might need more like 500 Gallons of fuel for one trip round the field.
I know a Ex REME Tankie and he says most common fault is the L60 leyland engine governor packs up and engine revs to destruction.
Yeah... hearing you there mate..........I guess the 'miles per gallon ratio' would probably be more like a 'gallons per mile' figure ! heheheh!
......hey off topic a bit I know but ..... weren't some of the later Chieftains fitted with a 'multi- fuel' engine of some sorts or am I thinking of another tank ??