If your car is on jacks-

[Dhos1]

If your car is up on jacks please take a picture of your driveshaft. I want to see how far it slides into the tail of the transmission

 

[TIMINATOR]

We have always installed customs measured at 1" out from fully seated AT RIDE HEIGHT!
Aftermarket control arms, lowering/ raising springs, adjusting pinion angle, shock length, 9" rear use, and/or coil overs WILL change what ride height length will need to be.
TIMINATOR