Although I'm not at home for a few days so can't lay my hands on it, Peter Dron's book M3W back to the future! discusses final drive ratio's, listing OE and hypothetical higher ratios which would allow 60mph in second.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone