Mustang posi fit? How about 3.73's?

[v6underpressure]

I was going to search the junkyard and I was told that there are 7.5 rear end posi's in mustangs that I can swap in. Is this true? Also, I currently have a 4cylinder automatic 98 XLT 2wd ranger which has 4.11 gears in the rear. Could I swap a set of 3.73 gears in there for better gas mileage? WILL it get better gas mileage? And if so, what parts would I need? I am sure I would need the gear for the tranny etc? Thanks for any help guys!!!

 

[4x4junkie]

I doubt a switch to 3.73s will increase your mileage much, if at all. It will certainly make your truck more sluggish though. I'd hang onto the 4.10 rearend.

What size are the tires on it?