Determining Drive Shaft Length

[jefflock]

I'm in the final stages of putting my 68 Dart GTS back together. I moved the springs back to center the rear axle in the wheel opening.
How far does the front yoke need to stick into my 727??
How much slack do i need between the end of the drive shaft u joint and the rear end?
How much is to much slack between the rear u joint and the rear end?
Thanks,
Jeff

 

[bbrroowwnn]

push yoke all the way in the trans as far as it will go....then measure from the centerline of trans universal joint to centerline of rear end universal joint......then once you have that measurement subtract an inch and that is your drive shaft length measurement

 

[Plymouth 65]

Typically one inch of travel is fine. Push the slip yoke all the way into the transmission. Pull it back out one inch and measure the distance from u joint to u joint center. Make sure your car is on the ground with it's weight on the suspension. 65'

 

[hemi446]

One more item is make sure the car is complete with interior and all the body parts in place. Adding weight to the center of the car after the fact will lower the car and could make the driveshaft to long.

 

[Dana67Dart]

How far back did you move the rear back

 

[jefflock]

If I remember right around 1". When shoved all the way in I have right at 2 1/4" of room. So take 1" off for travel looks like about 1 1/4" longer. Currently I don't have all the interior in the car. Only drivers seat other than it nothing.

 

[MileHighDart]

push yoke all the way in the trans as far as it will go....then measure from the centerline of trans universal joint to centerline of rear end universal joint......then once you have that measurement subtract an inch and that is your drive shaft length measurement

This is how I just did mine and it fits perfect.

 

[jefflock]

Thanks for the help. Looks like I'll be getting a new shaft made.

 

[fishy68]

As stated an inch is about as perfect as you can get. It allows plenty of suspension travel and good spline engagement. I have ran them as tight as 3/4" and as loose as 1-1/8" without an issue but that wasn't on a race car either

 

[Car Nut]