Wow, I never knew about the five pot, this and many features of the 2000 engine show just how advanced Rover became under Spen' King's guiding hand. Just a couple of points on other matters here though, the Triumph Six is a very small engine not only did it fit in the GT6 and Vitesse chassis it could also be shoehorned into the Standard Ten (did it in about 1971.) I actually think that it may not be much bigger that the P6 four cylinder, remember the Triumph is a much more simple design. The Lucas Opus I referred to above was an electronic ignition system only and it worked just fine on Cosworth DFV F1 engines, the Lucas mechanical fuel injection system as used on TR6 and 2.5 PI was another story, although some of it's problems were down to poor maintainence and/or bad location by the manufacturers. As to factory injection on the 3500 I suspect that if indeed this had ever been considered it would have been for the US market only as a means of meeting ever stricter emmision controls. If the intent was to produce more power then surely Rover would have gone for improving the porting and cylinder head profile first, followed by weber 44 IDFs.