Will changing the differential ratio alter the speedo?

[BenBS]

Hi guys!

Long time no post..

As you probably won't recall, I asked quite a while ago for some opinions on an E28 525i. Well, I bought it!

So although this question relates to an E28, it's the same thing underneath really.

So, will changing the diff for a different ratio alter the speedo reading? I'm looking at an E12 M535i LSD.

(EDIT) Nevermind to the question below, I've realised it won't fit since it uses mechanical speedo drive. But the original question still stands, will the diff change the speedo reading?

Which brings me on to my second question for the BMW gurus out there, will an E12 diff fit an E28? I don't see why not, since it seems you can bolt pretty much any BMW diff to any BMW if you change the output flanges.

Some photos for your enjoyment. Unfortunately the car is a bit less presentable than when these photos were taken as rust is taking hold, but that will be fixed, and it will be glorious once more!

http://homepage.ntlworld.com/astonman/picmanoulton