Drive shaft lenght

[sixty9xtc]

Does anyone know what the correct travel the slip yolk should have on the driveshaft.

 

[Supershafts]

Mopar suspension, bottom it out with the suspension loaded and pull it out 1" or 1.15" , then measure center to center and that is the shafts lenght it should be

This way it doesn't slam the back of the trans.