About $1500 in price, a slightly higher weight rating, and about 2 inches of clearance. All parts appear to be identical otherwise. This has been a topic of great discussion on Ford-Diesel , if you want to learn about Fords, this is the place to be! A word of caution: It's VERY addictive!!!
Thanks Brickman, I saw it. I appreciate all your help. I've decided to go with the 350 V10 4.3 axle. The guys on the Ford site recommended the 4.3 over the 3.73. Might burn more fuel but I think I'll be happier with the 4.3.
Good luck man. I know you will like your new truck. I have a 3.73 with my PS. The only time I wish for a different rear is when I am over loaded, (I do it all the time) and trying to start off on a hill. The rest of the time I roll right along. Dunno on the V 10, but with the PS you got enough balls the 3.73 rear would give a little better milage. I have a 75 HP upgrade chip on my PS, I get 8 and 9 mpg loaded. By loaded I mean about 15K empty and 24K to 29K loaded. But then I drive balls to the wall too.
after doing much research for myself, i ahve found that the only difference in the two of them are the spacer blocks in the back and the tire size. this allows ford to put a higher gvwr on the truck. if you have any more questions on specs let me know. i have pages upon pages on the smallest details.