What I have is an EFII Futura station wagon running the diff is was originally built with. I also have the LSD diff head taken from an EFII XR6 car - it’s 3.45:1. My plan is to pull out the S/W diff head and replace it with the LSD from the XR6.

It looks like I have over simplified this project and that a straight swap may not be possible because of something to do with the spline count of the axles and that also the drive shaft may not be a simple fit up to the replacement diff head.

The question is that are these real factors that I need to take into account and are there any other potential difficulties I need to be aware of?

Any advice would be more than welcome.

Bruce.

i am NO expert [as yet! ] if they are from the same model & same[ish] year shouldn't they be the same spline?

i know with the EA?EB they did change the splines altho not sure when