Tranny? You mean I need a Tranny?

I've been wrenching on this '47 Dodge for almost a year now and i'm finally ready to complete the running gear fab, but need some advice.
The original flathead six runs like a clock, was rebuilt in '57 and has low milage on it.
My perfect-world scenario would be to replace the original 3-speed trans with an automatic, but i am not sure which way to turn.

What trannies can I use?
What adapters are available?
Should I change out the stock rear-end too? To what?

Any input would be very much appreciated.

 

This sounds like a horrible idea to me. I guess it's not a Hot Rod. Right? Later Plymouth and Dodge sixes came with Powerflite 2 speed and maybe TorqueFlite 3 speed power eaters. I guess you could look for a '55 to '61 or so six cylinder automatic doner.

 

Automatic transmissions use up some of the horsepower produced by the engine. If I had a nice running flat 6, I would leave it with the standard trans. The even better senario would be a v-8, with auto trans swap if you were spending moneys and time for the automatic transmission swap anyway. You would be happier with the v-8 power, added with the no need to clutch and shift all the time. This is only my opinion or judgement.

 

Ok folks. I understand the desire for traditional and mainly stock, but I am looking for an easy ride and the ability to do highway speeds.

I could swap out the 6-fer-an-8, but the six is cool and with a dual intake and dual exhaust, it runs and sounds great.

I'll look around for a '55 to '61 doner...

any other ideas?

 

factory stick with overdrive would be my first choice,

 

A very good point, and after some research I have learned that an A-833 Trans with built in overdrive from an original A-Body or F-Body or even truck ranging from 1964 to 1989 will do the job. It means still having a manaul trans, but putting a 4-speed stick on the floor and perhaps even use the rear end from the same vehicle.

Of course, this is all at first blush and more research is required.

Anyone have any experience in this?

 

If you're only concerned about highway driving, you might want to keep the 3 speed manual trans, and swap the rearend for something a bit newer (which would also give you better rear brakes). 60s 8-3/4" rearends from midsize cars are pretty easy to swap into your car, but also kind of pricy in these days of high dollar muscle cars. You might find than an 8" ford rearend will be a great substitute...same wheel bolt pattern, and most of them had highway gears (although they might be a bit too higway, as 2.78 or 2.80 is a common ratio)

 

I think I agree De Soto!
I am going to finish the floor and then rewire and plumb the car and get it back on the road.
After I drive it for a bit, i'll see what it's like and go from there.

Thanks for all the input.

 

Keep in mind that a non-lockup torque converter in an older transmission like that will have at least 500 rpm of "slip" at highway speeds. That means that even though the final drive ratio of the trans is the same, an automatic car may be turning more rpm at the same mph.