Need some help and idea's on this one .

First I have a FMX 3 speed auto trans with 3:55 rear 26" Tires 351W

With this setup it just runs at to high of an RPM at highway speeds

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I have looked an AOD trans and have got input from good trans guy saying that they are hard as hell to get setup right with the throttle position cable and even then he doesn't think I would be happy with how it shift.

Anyone have the above setup ?

Next is an AODE On this one I am being told that is would shift fine until...it want to down shift from the OD to 3 and that with the 3:55 rear end it would shift down very very hard . Plus the added price of the controller.

And last for now change the rear to 3:25's one I am not sure that would give me the RPM drop I need and I like to zip of the 3:55's

And before you ask ... I don't have a tac I am using the dam that is to high RPM system. Thoughts ? Idea's ?

 

The 3.55 rear should be fine with any overdrive setup, I don't think the change to a 3.25 rear gear will provide much change or is worth the effort or expense, IMHO.
I put a T-5 transmission and a 3.50 gear in my '70 Mach 1, which originally came to me with a FMX trans and a 3.00 gear, it now turns at 2100 RPM at 70MPH which is very comfortable.

 

Thanks for your input... The T5 is electric controlled ? And if so how did you get your speedometer to work ?

 

The T-5 trans is all mechanical -
Are you referring to the speedometer sensor?
The T-5 drive gear will accept an electronic sender or mechanical connection for the speedo cable and will accept your original 1969 speedo cable. I have not run into any compatibility issues with any of the Tremec transmissions that I have installed.

 

Thanks for all your help