I have a 3:89 gear with a 31" tire and T5 overdrive. It runs 2500 rpm at 80.

Kenny  Onalaska, Texas

Back in the late 60's, I replaced the fordo with a T-85 O/D in a 55 bird. My friendly junkyard guy went looking for lower rear gears, and came up with an I-6 O/D car with a good rear end. It was the 4:27 Dana mentioned above. It bolted straight in with the addition of lowering blocks, as I recall. I don't know what gear ratios were in that T85, but it made a good 70mph combination on the freeway, and really pulled well in 1&2. It was a .060 over 312, 11.25:1, rpm 300 isky cam. Tires were recaps off one of Dad's cars, and a little taller than stock.

I don't know about the open carrier, but the "posi" type unit I have now is 3.7? and down. Going to the 3.9's or higher requires a change.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I see no problem with the 3.54 with overdrive if the cam is pretty well stock or mild.  My final drive ratio in my 56 Tbird is 2.45 and works OK But I am pulling my cam down by widening the lobe separation from 110 to 112 degrees. Keep in mind my cam is a long way from being stock.

-Gary Burnette-

GooD discussion!  I like Doug's comment as the capstone.  "Consider the WHOLE package".Think about what Ford provided in equipping their vehicles from the factory in '57 (according to the Ford Owner's Manual)...
                                                        CARS                                  STATION WAGON
                                            I-6 engine         V-8 engine3 speed Standard                3.70s                 3.56s                              3.89s   w/ Overdrive                        3.89s                 3.70s                              4.11s

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Dan, Remember with the OD your effective top gear would be 3.54 x  .7  or .63 (don't know which ratio you have).

Frank/Rebop

Bristol, In ( by Elkhart) 

Well, from the testimonies of "real world" experiences it looks as if I should probably wait and experiment a little. I just may use the 3.55 rear end that is under the car now, and then go from there. I would imagine the first thing I need to do is check the gear ratios in my 3 speed/Overdrive transmission to see what I would be pulling in 1st gear and so on.As it happens, a buddy of mine has a lead on two old 56 Fords sitting in the woods near his home--- we will see what he comes up with, and my dad happened to call yesterday to let me know that he is going to see an older fella that used to race 56's at Bowman Gray Stadium in North Carolina years ago. The gentleman has a 56 race car and a slew of parts he wants to sell my dad so we will see how that ends up too.thanks guys

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Daniel.  I run a 3.56:1 rear end ratio with a T85 overdrive in my ’55 Customline.  It originally came with a 3.89:1 rear gear but the 272 in this case is much happier with the 3.56’s at highway speeds.

Lorena, Texas (South of Waco)

Seems a little low to me 3.54 X .7 = 2.47 final drive in OD.  A small dia tire might make it OK but I would say something like 3.89 or so would be a happier set up.  You should also consider what the 1st gear ratio is.  A close ratio trany ie around 2.20 to 2.40 1st gear would be poison for this set up especially with a somewhat bigger cam, a heavy car, and tall dia tires.   Consider the whole package. 

Doug T

The Highlands, Louisville, Ky.

I have mine in my 52 Mainline ute with 302w and AODJust idles along @ 70mph,  great for cruising.




South Australia

Dan:If I remember correctly, to install a 4.09 or lower gear in that housing, you also need to change the carrier that the ring gear bolts to.  I have a 4.56 gear in my '56 Bird from a Studebaker Dana 44, I used the Stude carrier, the Ford side gears, and the Stude ring and pinion.  Stude had 4.09, 4.27, 4.55, 4.88 and 5.13 gearsets "back then", you may be able to find them from the Stude parts vendors.  Oh, I just remembered that Chev S-10 4wd used Dana 44s and their gears "almost fit" the early Ford Danas.  S10 4wd shops may be able to help here.

John - "The Hoosier Hurricane"