I have a 2004 F-150 Heritage 4X4 4.6L V8 with 3:31 in a 8.8. Note this is a heritage (baically same as 97-03) not a new body style.

Anyhow, I have a 3" body lift w/ 35's. I've been doing some research trying to find a suitable option to optimize gas mileage and bring it back to as close to stock as possible.

I'm a claims adjuster for a major automotive company and deal w/ used/reman parts dealers on a reqular basis. I've been looking for gears or an entire unit to swap out. I had one dealer tell me he had a used unit out of a 2005 new body style w/ somekind of payload package w/ 6k miles on it that may work. He wasn't exactly sure. But it's 10 1/4" w/ 4:10. If this would work, it would be pretty awesome considering the price he's flashing at me for the entire unit.

What are my options, if any?

Thanks guys.

 

There would be some welding, I think the shock mounts are at different location. I just put 3:73 in a friends 8.8 mustang. He picked up ther gears from Summit (Ford racing) for about $250, and install kit for $90.

 

I measured up the diffs yesterday. The diff new body style is about 1 1/2" longer. The spring pads on the old style truck are a 1/2" wider. Also the shock mounts are in the wrong location, (inside the spring pads). I would just buy gears, way easier IMO.

 

LOL. Yeah I spoke w/ a friend @ a dealership and he just thought I was crazy! So yeah, just buying gears is going to be the easiest or should I say only thing to do. Thanks guys.