[Sgt RedMan]

Whats up rodders?
I have a Ford Y block built to 289ci mated to a 1955 Ford three speed with electronic overdrive and a Ford 9 inch rear axle from an early 70's Ford truck.
I am not sure of the current gearing of the axle yet as I have not started to
work on it, but the question was recently asked what gearing I was going to use. This is a good question and I have no good answer. Any suggestions?
There is no body as of yet, probably will be a custom build. Just a frame, Model A, front axle is a straight custom build with Model A spoked and I have a set of 16in rims that I am going to put on the rear.

So, what do you think?

[timothale]

With the overdrive ratios from 3.5 to 4.5 would work

[Irelands child]

"Assuming" that driveline came out of a 'run of the mill' '55 Ford, that OD transmission was probably backed up to a 4.10/11 differential if it's their conventional drop out the front version. If it's a station wagon or Mercury and removes from the back, then it will probably be in the 4:20's.

The only way to tell for sure is to pull it apart and count teeth as Ford has a 'history' of strange parts for reasons only they knew

[timothale]

If the truck rear end hasn't been messed with it should have a small metal tag with some numbers that you can decode. Or turn the drive shaft and count how many turns to get both wheels to turn over one time or how many turns to get One wheel to turn over Two times then do the math 3 and 1/2 turns = 3.50 ... 4 turns and about 30* 4.10 or 4.11 ( 30 * / 360*)

[Sgt RedMan]

I am sure the metal tag is still there, I havent removed the rearend from the truck yet. It is hard to get motivated in 110 degree temps. I will probably teardown the rearend and do a complete rebuild. I have no engine or transmission, front clip or cab, so I have no numbers to go by other than the tag on the rearend. I have a 1999 F150 with a 4.6, automatic, and a 3.55 limited slip. I am not happy with performance although I know that the rearend itself is not to blame. The 3.55L is good for fuel mileage, just not performance.
I am thinking about moving to a 3.7 to 4.1 area of ratios to get performance and still make this affordable to drive whenever I like.