Driveshaft Question..

[nodemon]

My 72 Demon is a 3spd manual floor shift car...I'm putting a 4spd in it.. Will the original driveshaft work..?

 

[junkyardhero]

230 is the same length as 833/904 so you're fine on shaft length, but you'll need to swap our your slip yoke to match whatever flavor of 4spd you're putting in.

 

[Professor Fate]

Depends on the four speed that you're dropping in- if you're using a '66-'67 833 which has a 26 spline output shaft, it's a drop-in.
If you've got a '68 and later four speed, you'll need to swap to a 30 spline slip yoke.
This is all assuming you're installing an A body four speed...

 

[Dana67Dart]

And don't forget to match the yoke u joint requirement small u joint or large.

There are combo u joints (big on one side and small on the other) but why muddy the waters.

 

[NoCar340]

Depends on the four speed that you're dropping in- if you're using a '66-'67 833 which has a 26 spline output shaft, it's a drop-in.
If you've got a '68 and later four speed, you'll need to swap to a 30 spline slip yoke.
This is all assuming you're installing an A body four speed...

Most A-/F-body aluminum overdrives are also 26 spline. A 30-spline aluminum short-tail is a rare bird, but they were made. The only 30-spline A833ODs I have are a cast-iron case, high-helix '75 A-body and a couple of truck transmissions.

 

[Professor Fate]

Most A-/F-body aluminum overdrives are also 26 spline. A 30-spline aluminum short-tail is a rare bird, but they were made. The only 30-spline A833ODs I have are a cast-iron case, high-helix '75 A-body and a couple of truck transmissions.

Interesting... I have had the opposite luck, currently have two F body aluminum ODs sitting under the bench, both 30 spline outputs. I know they're out there, but I can't honestly say I've ever run across a 26 spline OD in the flesh. Luck of the draw, I guess. Slant 6 vs V8, maybe?

 

[NoCar340]

Interesting... I have had the opposite luck, currently have two F body aluminum ODs sitting under the bench, both 30 spline outputs. I know they're out there, but I can't honestly say I've ever run across a 26 spline OD in the flesh. Luck of the draw, I guess. Slant 6 vs V8, maybe?

It's entirely possible. I've never really looked into it. I've bought and sold quite a few over the years, and the two '75-'76 iron-case ones I had were the only 30-spline short-tails. Last time I looked at Brewer's, the short 30-spline aluminum tailshaft housing--which is not the same as the Direct Connection part, but probably works as a substitute--was considerably more expensive than the 30-spline. Same situation for the A833OD 30-spline mainshaft.

I never worried about it much because the only reasonably-powerful engines I plan to have ahead of an overdrive are both stock-stroke small-blocks, and both are E-bodies. I'm actually mid-assembly on one for my '71 Challenger, which is a truck overdrive gearset swapped into a close-ratio, 307-bearing iron main case. The iron case eliminates the floating countershaft, but more importantly fits the original 3-speed bellhousing. I'll do another for my '74, but it will only get swapped in for long trips. I have family all over the country.