23spline & 18 spline tailshaft same?

23spline & 18 spline tailshaft same? - 04/23/09 03:21 AM

I am wanting to change the tailshaft on my 69 or back hemi 4 speed to a 70 or up dual pad tail shaft and have plenty of 23 splines, are the tailshafts the same?

Posted By: fastmark

Re: 23spline & 18 spline tailshaft same? - 04/23/09 03:40 AM

The tail shafts are slightly different. The hemi box uses a bigger rear bearing on the tailshaft. I am pretty sure you can just use the smaller bearing and the 23 splined tail shaft and shaft and be ok. I think I have done that before. It has been a while since I have been into one of those and I don't really do that many of them.

Posted By: Stanton

Re: 23spline & 18 spline tailshaft same? - 04/23/09 04:21 AM

I don't think the tailshaft bearing is different between the two, only the input bearing. Why not go to the Passon or Brewer website and see what you can find ?

Posted By: Dan Brewer

Re: 23spline & 18 spline tailshaft same? - 04/23/09 04:31 AM

Quote:

I am wanting to change the tailshaft on my 69 or back hemi 4 speed to a 70 or up dual pad tail shaft and have plenty of 23 splines, are the tailshafts the same?

66-7 18 spline will be a 307 brg
68-9 18 spline will be a 308, same as the C99539 70-Up B/E tailhousing

Posted By: torkrules

Re: 23spline & 18 spline tailshaft same? - 04/23/09 04:32 AM

Quote:

The tail shafts are slightly different. The hemi box uses a bigger rear bearing on the tailshaft. I am pretty sure you can just use the smaller bearing and the 23 splined tail shaft and shaft and be ok. I think I have done that before. It has been a while since I have been into one of those and I don't really do that many of them.

The 18 spline box uses the 308 (large bearing) instead of the smaller 307 bearing. The snap ring also retains on the bearing with the 18 spline tail instead of on the extension housing.

You can use either extension housing as long as you use the appropriate bearing. The output shafts are the same.

I redid my 23 spline box with 18 spline guts and used the 23 spline output shaft, extension housing and bearing.

Posted By: JohnRR

Re: 23spline & 18 spline tailshaft same? - 04/23/09 12:40 PM

Someone gave the correct answer above , big block applications of the 23 spline with the B/E tailhousing use the 308 bearings both front and rear , the OP says he has a bunch of 70 up b/e to chose from so he can probably find the tail he needs. OR you can just switch to the 307 bearing if you don't have the right tailhousing , trans will be fine for as little as these cars are used now .