To further kick a dying horse er.. thread:
My recent experience running at highway speeds (almost Canada to Arizona and back) tells me that a 4.57 axle ratio is about all you want to pull when loaded. I don't think it would be happy pulling a 4.10. These old trucks will haul a heck of a load and not complain but they just get slower and slower in the hills as they get heavier; I recently weighed out of the gravel pit at 12,500lbs. Last summer I changed from a 5.13 to a 4.57 to go with the 261 and so I could have some selection of tires and not be forced to use a 33in. 255/85xR16 of which there are about two choices, noisy and noisier, off-road deep lugs doncha know. But with the full load of the camper's wind resistance and weight I almost with I had the 5.13 back. With 2.65/75 R16s I'm running 2550 RPM at 60 in overdrive (17%) and 2850 was better for the cam I'm using. So I spend a lot more time in direct drive. I need a gear in between, maybe a 4.88 if I could find one. With a smaller load the 4.57 is great;
