Its an interesting question and one which I cant claim to be able to answer with any degree of authority. The engine in my Ford is not the original engine although its is definitely a wartime unit, that said everything that I have worked on, starter motor, exhaust manifolds, brakes, carb, dizzy and fuel pump are metric, shortly after I acquired the Ford the dynamo packed up so I purchased a Power Master alternator form the States the one that looks just like the dynamo. When I came to fit it the original bolts were no use as they were metric so I had to re tap the thread to take the metric bolts. A friend of mine has a Poissey built F198t and the engine on that is also metric. To the best of my knowledge all European engine and vehicle manufacture was and is Metric, the exception being us Brits who use good ole AF.