Hi Brownrangie, mine's a v8. Besides speedo and odometer readings being out, when you put your foot down anything below 2000rpm the response is hideous (compared to it's spirited performance with the stock tyres). The new tyres have taken me out of the engines power band especially at highway cruising speeds (100kmh @ 2000-2050rpm and 110 is roughly 2250-2300rpm), to get into the power band about 2500rpm in 5th I'm going too fast for the speed limit, which means a lot of 4th gear down changes on inclines and head winds.
But take them offroad and you really notice a positive change. Low range performance is still good.
Contacted Great Basin Rovers, and Bill is of the opinion that even standard the disco's didn't have much 'reserve' gearing, meaning anything you did besides increasing engine performance negatively impacted performance to the point it becomes painful to drive, ie heavy bars, racks, big tanks, lifts, taller tyres, towing trailers etc. So I've recently ordered 4.11's from them and this will bring me back slightly shorter than I was with stock tyres. I will also take this opportunity to drop in a detroit locker in the back and truetrac up front.
