I'm going to close this whole subject out.  I got the car running and took it out for a drive for the first time since I swapped the transmission to a Mustang 5 speed w/overdrive.  The engine turns 2700 rpm at 70 mph which is just about perfect.  Apparently I have a 3.55 rear end.  Thought I had a 3.31.  So no need for a different rear end.  Thanks for all the replies.

The shock brackets are different on the Mercury rear end and also wheels are different bolt pattern  Carl   

The pre 1957 Ford pickups also used the Dana 44 axle.  

Jack    I have a Dana rear out of a low millage 1956 Mercury with O.D. that I drove and it worked as it should  teeth count is 45/11 =4.09  ratio    $175.00  Call Harry Hutten Jr. 513-868-3311 located in S W Ohio

If you are still looking a rear end...3.89 or 4.11 overdrive units, call VANPET SALES in Balavia, Ohio (near Cincinnati) PH 513.724.9488.
They have all kinds of parts for trannys and rear ends.
Good Luck,
Tim
Hot 'n Humid, FL 33706

yes at least in canada

Just by way of clarification.. I believe the mentioned Dana rear axle was also found in 55-56 Sedan Deliveries..


Paul

My 55 TBird has it's stock T86 3 speed O/D transmission and Dana 44 rear.   This option alone is what sold me on owning this car.   My engine is a slightly modified 1957 292.  The tag on my differential says it's a 4.11.  I"m not sure if that is correct. I am running 215/70R 15 tires all around.   As you would expect, acceleration in first gear is brisk.  Second gear and second gear overdrive are perfectly matched to this engine's torque curve.  Driving around town, you don't even need the other gears. Mid range torque is impressive in second gear.  I only use third gear out of town.  At 60 mph in third gear overdrive, my tach reads less than 2,000 rpm.  Ford's overdrive was years ahead of it's time.  I've thought about switching to a T10 or T5.  Overdrive is how my car was built and I love it the way it is. 

I agree meteor. After I put a Cruise-O-matic behind my 292 I went to an 8.8 with a 2.74 gear and it’s perfect for how I use my car. It is not a dead player off the line and way better than starting in second with a 3.21. Yes when I had the lower rear and the 3 speed it was good but a noticeable difference at freeway speeds of 65-70 the car was quieter and just easier feeling.
These cars were built with a 55 mph speed limit for most of the country and for the most part poorer roads.
I’m long done with jackrabbit starts at 76 but can watch them with fond memories.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

why do people miss the strong part of the y block engines,low end torque. so i say use the low end tore,stay away from low geared rear ends and radical cams. by using  a grind from 1957 mere 312 on a 292 and a 3.5 axel makes for a awesome launch. just my take. shad bolt cams in vancouver has ground several for me with excellent feed back.