Rear lift - driveshaft problems?

[1971ford]

How much can you lift a highboy in the rear until you get to the point where the driveshaft needs to be lengthened?

Looking to add enough leaf springs to the rear packs to give about 2" of lift, i am hoping that the driveshaft does not extend too much to where if i flex the truck on the trail it will not try to pull the driveshaft apart. The front i lifted 3.5" and the driveshaft won't even bolt back into the yoke while being 100% extended, and at ride height (re-tubing it now).

[averagef250]

A high pinion front axle will make that front driveshaft fit just fine.

You can get a good approximation of where your rear driveshaft situation is going to be by unbolting it at the rear end yoke and dropping that end down exactly two inches vertically.

[CrypticRacer13]

Thats the way we did it on the jeep