Hi all, I am new to the forum.

I have a 1966 Cutlass convertible with a factory 3 speed, A/C, PS,PB. The hurst shifter rattles very badly. To fix it, I have been told the tranny must come out. When I look underneat, it says FORD (?). My question is should I use the opportunity to upgrade to an M20? I am open to suggestions. Want to spin less RPMs on the freeways.

 

Yes, Olds used the Ford 3 speeds. I believe the final drive ratio is the same on 3 and 4 speeds, so to get less RPMs you would need to go to a 5 speed.

 

Given it is a 3 speed Ford box, would a Ford (Borg Warner) OD be an option?

 

GM used the toploader three speed from 1965-69 as the HD three speed floor shift option. This trans uses the Ford bolt pattern to the bellhousing but has a unique GM input shaft. Other Ford transmissions do not bolt in because of this.

Your factory bellhousing has both the Ford and Muncie bolt patterns. A Muncie swap is easy. As noted, you need to determine exactly what you want out of a trans swap. ALL GM 3spd and 4spd transmissions have a 1:1 final gear, so only an OD trans will change that. Also, note that the 3spd first gear is not too far from first in the Muncie. Changing to a four speed will not appreciably change off-the-line acceleration, either.

Finally, why does the trans have to come out for a shifter problem? The shifter can be removed separately. If the vibration is really a symptom of a different problem, however, that may require trans removal.

 

My reaction was similar to Joe P's in terms of trans removal to solve shifter rattle problem. Did not make sense to me to have to go to that extreme to diagnose/resolve rattle problem?

 

You'll need an overdrive trans to lower cruising rpm.

 

If you want to stay 3 speed you can do a Saginaw with Borg Warner overdrive

 

Thanks for all of the feedback. I will be searching out prices of each option and instillations costs. Stay tuned.