Your's is square arch Steve.
Paul, I know all about 'SAR'. I had a ride in it at Brooklands once. I happen to have exactly the same engine and gearbox here, which I'm not going to use now. The least powerful Busso, yet the dark blue car was anything but slow. Being in the passenger seat of a car being driven enthusiastically on private land may have had something to do with that?! It certainly wasn't lacking.
Bookmarks