My reading indicates that 240s were available with 3.31:1, 3.54:1, 3.73:1 and 3.91:1 final drive ratios. Normally aspirated sedans and wagons with M46 had a 3.31:1 rear and the automatics were 3.73:1. Turbo cars had a 3.91:1 box. Is this correct? Which cars had a 3.54:1 ratio?

I have also been told that the gear set can be swapped for one out of any RWD vehicle that has a Dana diff. I believe that my '86 245 has a final drive of 3.31:1. No label on the diff, but judging by how tall the gears are (e.g. 3000rpm in 2nd at 30mph) and my gas mileage (30+ hwy) I would say so.

I would like to swap in a 3.54 or 3.73 gear, but I don't know which setup would offer the best compromise between performance and economy. Anyone?

I think that a 3.91:1 would be too much. I don't want to end up constantly "rowing" up and down through the gears in the city just to get to 60 a few tenths of a second faster.

Would appreciate any insight/comments/ideas.

Thanks again in advance...the BB has been very helpful!

-John