9inch and flathead with original tranny?

Hi Does any of you guys use a flathead, original trans and modern style rear axle? what ratios do you run? what did you do with the torque tube?

I have a 46 ford coupe with a french flathead 46 trans and banjo with 3.55:1 ratio. But I still want to get better highway speed and low rpm. Thinking about using a 8" or a 9" ( or some GM axle ) with like a 2.90:1 or something.

When i Changed from 3.71:1 to 3.55:1 I noticed a small difference in rpm at higway speed and 1 st gear is still useable for cruising. But i want lower rpm still.

I know a t-5 would be the best way to go, but we dont have a lot of them here in Norway, and just changing the axle would be easier and cheaper.

 

To keep the '46 trans you need the tailpiece off a pickup, it converts to an open drive.

 

i think going to an open rear with 2.90's is asking a lot for a flathead. Speedway offers a 3.25 for the ford banjo rear


http://www.speedwaymotors.com/p/3769,327_GETZ-High-Speed-Gear-Sets-for-1935-48-Ford-and-Mercury.html

 

9 inches absorb quite a few of your precious flathead hp as well..

 

Use a larger diameter rear tire!!!!!!!!

 

Find a nice T5 transmission

 

ok. thanks guys.

 

You have many options.

You can convert both your early Ford ****** & banjo to open drive, but that gains you nothing but a driveshaft & new rear suspension.

You can convert your early Ford ****** to open drive and swap in an 8" or 9" and new rear suspension.

You can convert your banjo to open drive and swap in a T5 (best choice, IMO).

You can run taller tires (won't gain much RPM reduction).

When you go to open drive, you will have to redesign the rear suspension. W/O the torque-tube, something else must take the rotational force of the rear - either parallel leafs or some sort of linkage.

 

Are GM 10-bolts common there?
Should be strong enough, & consume less power to turn.
Downside is that crownwheel changes must be made in the housing.

 

We run a 3.00 gear in our 8BA roadster on 28" tires...originally with the Ford three speed, it's a light car and that ratio seemed to be just fine. Since we changed to the T-5 a year ago we are satisfied that the 3.00 is still the perfect ratio even with the overdrive. The car will cruise all day long at 65 mph. That '46 is a lot heavier so I would think that maybe about 3.25 might be better.....the 3.00 would be a bit much.

 

Time for a Quickchange!!