If you have the stock 4 spd, your diff is 3.36. Unless you plan on changing to a five speed, you have two realistic choices - get another 3.36 diff from a 240 or get a 3.54 diff from an automatic 240. The 3.9 and 4.11 diffs are great IF you have the 5 spd. Without a 5 spd your rpms on the highway will be outrageous. 3.54 will get you off the line a little faster then the 3.36 and it will bolt right in.
You can try this Transmission Calculator to see what different diffs will give you with your transmission
Later,
Mike
You can try this Transmission Calculator to see what different diffs will give you with your transmission
Later,
Mike
