My 410 has a 2.88 LSD axle. I am not sure if this was from new or from when the car was restored in the early 90s by Spencer Lane-Jones (it was his own car, not a customer restoration). Sadly my rev counter is wildly inaccurate so I cannot report accurate figures. I saw 24mpg on one trip this summer, but 21-22 is more common on a long steady run. Spencer also told me he fitted mildly faster cam, and the engine was rebored so I think is about 5.5 litres now. Still on the standard carb.