I finally got my longer ubolts made so I can install my blocks in the back, but I got to thinking, will I need a longer driveshaft?

Scenerio:
My truck, XLT, 2wd, never had blocks in the back.

I spindle lifted the front 3". I put an AAL and 2" shackles in the back. But the rear is still 1" lower than the front. I got SebL's 1.5" stock blocks from his 2008 and I want to put them in.

I gather my leafs are sagging like crazy, cause after the AAL and shackles, my rear is lower than the front. I have "C" springs.

Will I need to lengthen my driveshaft with the extra 1.5" in the back?

I suspect I got 3-3.5" lift between the shackles and the AAL. So another 1.5" on top would bring me to 5" lift in the back, but lift from my sagging hieght.

No hardcore wheeling, light stuff, and logging roads to the fishing hole.

How can I tell if I need a new DS? I would hate to be driving down the road and my DS falls out.