55blacktie you are absolutely correct. I should have stated all Tbird FOM's are medium case transmissions.  Thanks for noticing my omission.

64F100 57FAIRLANE500

I'm not 100% certain, but I think 55-57 Tbirds were equipped with the medium-case Fordomatic. 

Perhaps a little off topic but, good question - I'm no expert by any means but most of the 272 and 292 FOM I believe were small case versions. 312 wagons, police and "E" code 1957's were medium case versions. Within the medium case versions, there were differences in line pressure calibration (regulator and other springs) and even the clutch packs could have a different clutch count depending on the application, just to mention a few differences. The metal tag will identify the trans. 

64F100 57FAIRLANE500

Pardon my ignorance, but is there a difference between an E or F code trans vs a C or D code trans.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

According to people on here that know more than I do, if the auto trans is leaking badly, it's likely that the front pump assembly needs a reseal & probably the front bushing replaced also..  Check into it? .. 

Paul

I would keep the parts as only 3% of drivers today can drive a standard shift car.

Even if you never intend to use take-off parts, I would hold onto them. If your car ever changes hands, the new owner might want them. I'm keeping my 55 Tbird take-off parts for that reason. 

You are not wrong, EXCEPT:
1) My car has the early '57 data tag format which does not identify transmission type or rear axle ratio;
2) In light of the above, I don't believe many would want to convert back to Ford-O-Matic from a proper '57 BW T85-R11 overdrive setup;  
3) There are a few '57 Ford restorers looking for an E/F Ford-O-Matic because some previous owner has removed one and junked it.

In summary: If I do the job right no one's gonna know the car originally came with AT, and resale value (if influenced at all) should go up.