This question may have an obvious answer. If you have the correct parts can a long tail shaft 400 be change to a short tail? The reason I ask I have 2 good 400 long tail but no one ever seems to need one.

 

I am interested in this as well I have a sweet long tail but need the short tail

 

Yes you can swap out parts to change a long tail into a short tail. the trans shop wanted I think 100.00 bucks for the parts when I was buying my kit. I didn't buy them but sure I will regret it one day

 

Or you can shorten the drive shaft and use as is.I use a local truck repair shop for making/changing length of drive shafts. They do rear ends also. Ken

 

What about the speedo I thought the long tail didn't have a speedo provision while the short tail had the speedo drive ? I do have another drive shaft but no speedo is a deal breaker

 

65-70 full size rwd Olds do not have the transmission speedo but all that can be added when doing the short tail conversion.

Henryy

 

Just so we're all clear, changing from long to short tail or vice-versa requires completely disassembling the trans. You have to swap the output shaft, which is the last part out of the case and the first part back in. The tail housing bolts on, but the output shaft must also be changed.

Note that some of those 65-70 Olds transmissions without speedo drive provision have the housing machined for the driven gear holder but simply have a freeze plug installed. These are easy to convert. On others, the hole in the casting is not machined, making conversion more difficult.