1972 CS M90 Conversion

[Deano1]

If it is the 4-speed auto I bet it will be 3k RPM or less. 4th gear is overdrive and the torque converter locks up so the ratio of RPM/speed is fixed.

You are correct. It is a 4-speed with lock up.

 

[Ian C]

That's too much gear for a dogleg

If it is I can go back to the 3.25

 

[Bert Poliakoff]

3.07 is the good ratio for a dogleg

 

[Ohmess]

3.07 is the good ratio for a dogleg

Agree. That's what I have in my 79 635csi.

 

[Bert Poliakoff]

and I have it in my '81 635

 

[sfdon]

Years ago I installed a dogleg in my 745i.
Drove me crazy with all the shifting and took it out a month later.

 

[ScottAndrews]

I think you will not be happy with a 3.64 diif

I agree the M90 has a lot of torque,and it can pull a much taller back end. Mine is, in think, 3.07.