My Daimler V8 auto is a lovely car, but undergeared by modern standards with a 4.55/1 diff, giving only 17.3mph/1000rpm. Changing the final drive to 3.77/1 would give a much more relaxed 20.9mph/1000rpm. Does anyone know if it's been done, and if the outcome was successful, especially with regard to acceleration and change-up/down speeds? And is a 3.77 crownwheel and pinion a straight swap for a 4.55 (apart from setting-up), or is it a more complicated job? Many thanks.
Many years ago I changes over my 3.4 Mk2 diff to a 3.31:1 ratio, the crown and pinion I stripped out of an XJ diff. Which is a complete strip and re-build of the diff using a special bearing on one of the pinion bearings, can't remember which one off the top of my head, but can look it up.
What your looking to do is simpler, as the ratio's your looking for are already used in the Mk2. The 3.77:1 was used in M/overdrive modles and the 3.54:1 used in the auto and none overdrive models. All your looking for is a complete axel out of one of the Mk2 models and swop it over for your own axel.