I once had a Vauxhall Victor up to an indicated 100 mph, with driver and 5 passengers, all pretty big blokes and all with only 1600cc. Then the head gasket blew! It was the FD (coke bottle shape model) and it was when 100mph was legal on motorways.
A few years ago police stopped a driver doing 100mph on the M11, in a Reliant Robin! There is a Reliant Robin currently on the road fitted with a 4.6 litre V8 from a Range Rover .