Gents -- please keep in mind we're talking about a 1-ton here. Not the same as talking 1/2-tons (hence the separate forum

), even when swapping bits around -- experience gleaned from 1/2-tons may not apply and could possibly be misleading.
Dave51chev -- I agree, but I wonder if his 15-inch tires are robbing him of any advantage the 4.10 rear gives. Like you say, the online calculator would probably tell us much.
Mike -- Do you still have the original HO72 axle? I hate to be the one to say it, but I wonder if you had left that in place and just switched out the center section, you could have kept your stock wheels and tires and been cruising around with the rest of us 1-ton drivers at 65 MPH not having this conversation ...

And by the way, I've been doing it on bias plys, 3-piece rims and ... gasp .... Huck brakes ... and to quote Morpheus -- "I am still here!"

John