So i'm in the process of parting out my 83 mustang. currently the stang has posi 3.73 gears and my truck has 3.55 standard open gears from the factory. My question is if i swap rear ends(assuming both axles are the same spline) will this affect anything besides the speedometer being off. such as electronic timings? will it throw off anything on the pcm? also any way to check the splines besides pulling one and seeing if it will fit in the other?
thanks in advance guys.

 

Are the axles long enough from the stang?

 

well i need to swap axles cause the mustang is 4 lug but wouldn't they be the same other than that. and possibly the splines may be different. i know most mustang guys look for 8.8 rear end out of junked f-150s and mostly just bolt up from what i've read