3 Speed to 4 Speed Swap

[mopardug]

Hi all. I've got a '74 Duster 318/ 3 on the floor. What do I need to put an 833 in her keeping the 318? And then the next question, when I upgrade to a 340/360, do I just change the driveshaft length, or is anything else different? Thanks

 

[67Dart273]

I'm not certain about bellhousings........not sure if all 3 speed bells are drilled for a 4 speed, or if the center hole is right.

"Shaft length?" They are the same you won't change the shaft unless you are changing rear axle.

 

[dano]

Rear yoke spline is different. I don't recall the spline count off the top of my head.

904 and 3 speed same

727 and 4 speed the same.

 

[mopardug]

So if I put a 727 front yoke on my driveshaft, it will work with the 833? I couldn't remember if the 3- and 4-speeds were the same length (A-Body). I've been told the Z-bar would work. but I'd need the 833, bellhousing, and I thought that someone mentioned that the shifter and rods were different also. That's been 10 or more years ago, and my brain cell just doesn't work like it should.

 

[sireland67]

Basically you will need bellhousing, trans, shifter and linkage and output yoke.
Pay attention to the u-joint size, you may need a conversion u-joint.

 

[67Dart273]

The shifter and rods are absolutely different. I don't know, you might be able to "hack" the rods, bend, splice, etc to work.

 

[AJ/FormS]

There were a lot of dual pattern, aluminum bellhousings.

There were some small spline A-body O/D boxes. They accept the 904 slip-yokes.

 

[mopardug]

Thanks for all of the information. Since it seems that there are many Bellhousing 'choices', do I need to look for a certain part #? Also, will my flywheel work? And will it work behind the 360?

 

[67Dart273]

Thanks for all of the information. Since it seems that there are many Bellhousing 'choices', do I need to look for a certain part #? Also, will my flywheel work? And will it work behind the 360?

Man you get more complicated!!! There are different bells in earlier cars. No you can't use "any" flywheel, that is dictated by the bell. So far as I know all cars use the smaller wheel, 130? tooth?

And the bell will work with a 360 but you need a 'weighted' wheel for the 360.

 

[AJ/FormS]

Or you can get a neutral balance 318/340 flywheel re-balanced for your 360, which is what I did

 

[mopardug]

67Dart273;1970995129]Man you get more complicated!!!

I'm sorry that this is coming off as being 'complicated' to you, I'm only trying to get the information BEFORE I spend any $$. I can't afford to buy stuff that I can't use, and 'half the fun' to me isn't screwing with something all weekend only to find out that I have the wrong parts. I have to piece this together and, as you know, there are many different parts to buy-some will work, while others won't.

 

[sireland67]

Before buying any of your conversion parts, I would source the actual transmission first.
Mopar used 3 different sized throw out bearing retainers, 4.3" 4.8" and 5.1" each require a different bell housing, unless you want to spend more money on conversion parts.

 

[67Dart273]

I'm sorry that this is coming off as being 'complicated' to you, .

That comment WAS meant to be lighthearted, K?

 

[AJ/FormS]

I took it so. But I kinda know you by now.

 

[chryslerfat]

As said start by getting a trans. and we can help you more from there with the other parts. The 66 will take the same yoke you have now on the drive shaft the newer one takes the 727 yoke and the OD takes the small yoke again. I would recommend staying away from the OD unit if you want to use your bellhousing provided it is drilled and tapped for the 4 speed.