how to tell the differnec between 99 and 03 irs

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07-01-2007, 02:27 AM

hari151

1st Gear Member

Thread Starter

Join Date: Jul 2006

Posts: 59

how to tell the differnec between 99 and 03 irs

I just recently purchase a irs unit to put in my 68 mustang....the guy told me its from a 03 cobra....how can i tell that its not from a 99........i heard the 03 were much stronger......please help

thanks

07-02-2007, 01:49 AM

mblgjr

Join Date: Oct 2006

Posts: 40

RE: how to tell the differnec between 99 and 03 irs

The biggest difference is that the '03 got 31 spline axles. They are also slightly fatter in diameter.

The next most obvious thing is that all 03/4 units came with 3:55's; whereas the 99/01 were 3:27

07-06-2007, 07:14 PM

Ellik

2nd Gear Member

Join Date: Sep 2005

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Posts: 315

RE: how to tell the differnec between 99 and 03 irs

the '03/04's have a larger diameter pinion flange as well, though thats easily changed. I believe the 01's had a 31 spline as well, but the '03 shafts are abit stronger.