Jim:
Thanks, your post was very informative. Would I see a big difference changing my rear end from 3.73 to 4.10? I'm towing a '68 Caravel with a 6-cylinder Ford Ranger. I've towed the trailer over six thousand miles, and so far it's been an adequate tow vehicle, although I'm always looking for performance improvements...I've added a Volant air intake and Gibson exhaust.
Jeff