Technical 1935 Ford Diff Ratio Advice

Hi,
Can someone give me some advice on working out Diff ratio, my current setup is way too low geared so im rebuilding the diff with a new crown and pinion gear set (I dont know the current diff ratio)
Some details below :
In have 1935 ford coupe ,currently building a new flathead engine for the car which will be a stroker engine 59a block
Running a 1939 Ford 3 speed
Running the standard Banjo diff
Wheel size is 15" with a set of Coker 560-15

Can someone advise of a good ratio for this setup or how to calculate what ratio is needed.

Thanks

 

The Car I need advice on.
Thanks

 

Hi,my 36 came with a 4.11 ,I ve changed it out to a 3.54 and I'm running 16 inch wheels and tires.The 4.11 had a tooth count of 9 on the pinion and 37 on the ring gear..There is also a 3.78 that has a tooth count of on the pinion and 34 on the ring gear.If you do a search on the Hamb there are several good threads on the subject.Not sure what is available in gears anymore.

 

Step one seems like figuring out your ratio, lots of videos on youtube of how to do this. If its undriveable id go 2 or 3 options higher, if its close, 1 can make a ton of difference. Difference in 3.91 and 3.73 behind a 383 with a 727 mopar is not being able to drive over 55 anymore and perfection

 

flip the rearend upside down,
there is a 1" wide cast web running from the torque tube to center section union...
it will have #s stamped into it... they are the # of teeth on each gear...
divide the smaller # into the larger one...
this will give you the rearend's ratio when it was built, could have been changed...

 

The solution is simple; find a Columbia overdrive rear end, the problem is affording it.