1957 Fordomatic

Habusailor

Habusailor

Senior Member
Is this transmission considered an overdrive transmission? I am installing a new Holley carb. And the instructions say I need a perch spring mechanism if I have an overdrive transmission. I don't think this is considered overdrive but want to be sure.

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The Fordomatics are not an overdrive transmission.
In '57 there was an optional 3spd manual transmission with overdrive.

The Fordomatic has a throttle pressure valve rod that connects the intake manif mounted throttle bellcrank to the transmission. It must be adjusted correctly for the transmission to function properly. (first photo)
The adjustment procedure is described on page 2-89 of a '57 Shop Manual.
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In the case of the overdrive equipped cars, they won't have all that throttle mechanism behind the carb like an automatic will have. The carb likely would need a place to attach the return spring on an OD or manual transmission car when an automatic car already has all that stuff. The "perch" refers to a spring holding bracket that sticks up from the manifold.

Nomenclature like this is confusing. They should be more descriptive of what they are referring to.
 
Thanks everyone for the help. I know what I need and don't need. Yes I am going to adjust the linkage once I install the new carb.

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