Did Ford offer an overdrive on the automatic in 55,56 or 57?

[Jayvee]

I understand there was an overdrive option on the manual, but how about the Fordomatic? If so, what are the identifiers? Thanks!

[miker98038]

No. None on autos in those days. Typically a 3.2x range for the rear drive. Did have torque converters though. Some Lincoln’s (maybe big Merc’s) used 4 speed hydromatics, but those came from GM. Had a lower first, still direct in high.

[rotorwrench]

Overdrive systems in automatics are a relatively modern thing by comparison to mid 20th century cars. GM and Chrysler transmissions as well as all the old Ford/Borg Warner Units were 1:1 drive in top gear. Borg Warner electric overdrives were added to manual transmissions as a sort of semi-automatic transmission. You could start from a stop in second gear with a shift to overdrive till the next stop. The clutch only had to be used for stops around town at low speeds. Ford addvertised them this way.

[Gene F]

I did not know this. I know my Skyliner is a pretty darn heavy car. With the factory optional bigger gear the car it is turning about 3,000 RPM at 65 or 70 MPH with the Ford-O-Matic.

[dmsfrr]

Originally Posted by Gene F

... With the factory optional bigger gear the car it is turning about 3,000 RPM at 65 or 70 MPH with the Ford-O-Matic.

That's fairly normal but it doesn't seem that way anymore as we've become used to the OD gearing in our daily drivers.
Even when driving at lower speeds in town these older 1:1 Fordomatics tend to feel like they aren't shifting into high gear. You may eventually get used to it???
.

[rotorwrench]

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Some folks are converting to the modern AOD with the cable operated OD set up. Conversion kits are available for the Ford Y-blocks.

[Gene F]

Originally Posted by dmsfrr

That's fairly normal but it doesn't seem that way anymore as we've become used to the OD gearing in our daily drivers.
Even when driving at lower speeds in town these older 1:1 Fordomatics tend to feel like they aren't shifting into high gear. You may eventually get used to it???
.

I am used to it. Here's the thing, at 70MPH (speed limit in some places here) it turns 3,000 RPM. Heavy car, with that gear is kinda chuggin'.

[Gene F]

Originally Posted by rotorwrench

Some folks are converting to the modern AOD with the cable operated OD set up. Conversion kits are available for the Ford Y-blocks.

Hmmm, from who? What transmission ? I'd sure like not to replace the floor if I ever need to change it. A 5-speed would fit, but hanging that third pedal in there sure would be an un-fun time.

[miker98038]

Here’s one of several. Number of guys here and yblocksforever have done it. I picked this one at random from a Google search since it’s a full article.

If it clears a bird, it’ll clear a passenger car. Getting the shifter to select low might be a problem, but realistically who needs to hold first gear if the governor is set up right. Cable adjustment is critical on these, best done with pressure gauges.

https://gearstar.com/blog/y-block-ao...Sd4yvHl7uJTj-N

[Jayvee]

To continue this conversation and in an effort to help others who might be looking for info on a conversion to overdrive, I am posting this information. I cant vouch for the accuracy of it because this it is generated by AI, but it might be good for further comments and maybe someone who has actually done a conversion can pipe in.

Great — for a 1955 or 1956 Ford Fairlane or Thunderbird with a Y-block V8 (typically 272, 292, or 312 cu in), here's a tailored guide to converting from the Ford-O-Matic to a modern overdrive transmission while keeping drivability, originality, and performance in mind.

✅ Best Overdrive Options for a Y-Block
�� 1. AOD Swap (Automatic Overdrive) — Most Practical Automatic Option
Best balance of modern performance and classic look.

Adapter Required: The Y-block doesn’t bolt directly to an AOD. You'll need:

Adapter kit from Wilcap, Bendtsen's, or Speed Gems

Includes bellhousing adapter, flexplate, crank spacer, and hardware.

Benefits:

Lockup torque converter = great highway efficiency

Fully mechanical — no computer needed

Maintains automatic operation

Widely available, rebuildable, and strong

Things to Modify:

Crossmember (relocate or fab a new one)

Shorten driveshaft

Lokar or custom TV cable for throttle pressure (critical for AOD longevity)

Possibly transmission tunnel clearance (not a major issue on T-birds or Fairlanes)

�� 2. Gear Vendors Overdrive (Add-on to Existing Ford-O-Matic or C4)
Best for keeping originality while adding overdrive

How it Works:

Bolts to the tailshaft of your existing 3-speed auto

Splits gears or acts as overdrive in 3rd

Maintains original trans and shifter

Pros:

Keeps car looking factory

Great highway RPM drop (22% OD)

Bulletproof

No major mods to tunnel or mounts

Cons:

Expensive (~$3,000+)

Some driveline shortening required

Requires careful measuring

⚙️ 3. Tremec TKX 5-Speed Manual (for performance builds)
If you're open to converting to a manual transmission

Requires:

Bellhousing adapter (e.g., Wilcap or QuickTime)

Manual pedals (if not equipped)

Hydraulic or mechanical clutch linkage

Driveshaft & crossmember mods

Pros:

Great performance and engagement

OD 5th gear (typically 0.68 ratio)

Strong enough for Y-block torque

Cons:

Labor-intensive conversion

Loses originality unless car was manual

��️ Suggested Conversion Package for Your Y-Block:
Option: AOD Swap Using Bendtsen’s Adapter Kit

You’ll Need:
Component Recommendation
Transmission Ford AOD (1980–1993, preferably 1988–1993 from 5.0 Mustang or Lincoln)
Adapter Kit Bendtsen’s Transmission Adapters for Y-block to AOD
Flexplate & Spacer Included in adapter kit
Crossmember Modify existing or buy universal
Driveshaft Shorten and rebalance
Shifter Lokar AOD shifter or reuse column if possible
Throttle Valve Cable Lokar AOD TV cable kit (critical to prevent AOD failure)
Rear End Ratio Ideal: 3.50 or 3.70 (works well with AOD’s 0.67 OD)

�� RPM Example (Assuming 27" tires, 3.70 gears, AOD OD ratio = 0.67):
Speed RPM (w/ AOD) RPM (w/ Ford-O-Matic)
60 MPH ~2,000 RPM ~3,000 RPM

Result: smoother cruising, less engine wear, better mileage.

�� Conclusion
Best Choice:

If you want to drive the car regularly — AOD swap with adapter kit

If you want to retain the stock transmission — Gear Vendors OD unit

If you're building a hot rod or performance cruiser — Tremec TKX 5-speed