Allards, Bristol, AC (Cobra), Gordon-Keeble, Nash Healey, Nash/Hudson Metropolitan, Jensen, Sunbeam Tiger
And then all the cars that used the Buick-designed engine sold to Rover:
Triumph TR8, Morgan, Rover, Range Rover and Land Rover, MGV8
And do you count the Ford engines found in many British cars, even though they are Ford UK?
And then there are a ton of Italians and French w/ American engines, including Iso, Bizzarini, Facel Vega, DeTomaso