drive shaft lenght

On a 65 mustang it would be 48.75"

:lol:

What car are you working on?

There are lengths in the factory parts book.

I did an 8 3/4 swap I to my dart ( from a 7 1/4)

The book said 51.62 (just a number, I don't recall the real number)

I measured the slip yoke C/L with the car sitting on the ground to a fixed point in the trans

After the 8 3/4 was installed I put the slip yoke in to the same dimension, and measured. I got 51.25 (again just the number I recall may not be correct)

I went with 51.5 figured it was a nice compromise.

In hind sight I should have gone with the 51.25.

The old seal did not have the extra extended part. The replacement seal does and under some conditions the lip of the new seal rides up on the tapered part of the slip yoke.

Moral of the story

Get it all assembled, set the car down on all 4s, put the slip yoke in to the correct distance, and measure