I.S conversion.. diff questiod

[jonesy318]

Hi guys, doing the m42 swap in place of the m40 auto set up and the original 4.1 diff is totally shot and ive bee given a good 3.64 diff with the bigger casing, can i use this diff and what would be the re-purcussions of this or do i need to get another 4.1 to use??? Any advice much appreciated

[Brianmoooore]

I wouldn't want an iS with a 3.64! It's a good ratio for a 325 with its torque, but even on one of these there's a noticeable drop off in acceleration compared to a 3.73. The M42 is an engine that likes to rev, and the reduction in performance would be very noticeable.

[jonesy318]

Thanks for that mr moore, best start looking for a decent 4.1 diff then