Rear Leaf Spring Shackle Help!

[CRD46]

I have tired everywhere to find the answer to this so I hope someone on here can please help me!!!!

 

I have a 2014 Silverado Z71 crew cab 5.3 and I'm trying to find out the torque for the lower bolt - (shackle to mount)  Note the picture with the yellow arrow pointed to the bolt.

 

I know the shackle to leaf is 85 lbs but no one can confirm the tightness for the shackle to mount.  Is it the same 85 lbs?  Is it more or less?

Any advice would help!

Thanks