Fastest unknown ... Was driving my 73 Mustang with a speedometer that went to 120 ... buried the needle. At the time I was behind a buddy in his 69 Charger with a speedometer that went to 160 .... He claimed 157 ... I don't believe that. Had a shop teacher that said over 100 mph, speedometers are inaccurate.
Have also done 100+ in a 78 Datsun, 76 Monte Carlo and 95 Thunderbird.
Now I keep things within 10 mph of the speed limit .... usually