Looking at an 89 vert its auto, thinking about doing a manual swap and people are saying I need to swap the rear end to a 4.1 rear end instead of the 3.9 that allegedly came with it.

I read through my paper work and brochures and it says the 89 auto vert comes with a 4.1 final drive. I thought all verts no matter if they are manual or auto were 3.9 rear ends.

Am I wrong ?

 

All S5-Convertible auto and any 5 speed NA/TII come with a 4.10.
The automatic coupe has a 3.909
Always check:
Specifications: What did the 2nd Generation RX-7 come w/. Options & standard features

 

I did check I just wanted to double check with you guys. Thanks for the help though.

Why do you think they changed it ?

 

verts get the 4.1 because of the weight.