As
@Quick_Shifter indicated make the switch the 2.5 race CO's and you'll never look back again. Regardless max lift height, contact the manufacturers and ask them directly. The consensus is typically no more than 2.5" lift but they all know their max limits for best ride.
Accutune did my Kings shocks (Tune, Revalve, new shock pistons on the rear, etc) so i'll trust them as they know my shock guts and i put mine at 2.75" with still room to go if i only had more spring rate , I have the King 14" x 500lbs/inch springs and i'm pretty much maxed out at 2.75" lift with the weight i have and i only have 3 more threads left to go. I added 14 turns more total compared to how they came stock because the steel bumper, winch rocks sliders etc. 500lbs is the softest spring you can get with CO's, max is either 650 or 700lbs depending on manufacturer. Next time i get my CO's out for maintenance i'll ask Acctune to change the springs for me and go 550 or 600lbs springs whatever they recommend based on my truck weight.
Once you get your 2.5 CO's, (hint, hint) , you can use this link to measure what you have and it'll give you an idea how high you can go, but again, contact the manufacturer if you want to know better.
accutuneoffroad.com
The King OE assembly measures 22.5" fully extended, Fox also measure 22.5", Icon measure 22.75"
Most shock manufactures can tell you more or less how much preload you can add before they say don't add more.
Icon says no more of 1.5" showing up above the collar, King mentions to keep at least 1" wheel drop out from ride height. This is what it came with my Kings.
2021-09-28_04-21-36 by
RAM RSM, on Flickr
I went with what Accutune recommended since they did them for me. They said no more than 21" of total shock at ride height. So i went up until the the COs at ride height measure 21". Like i said i have 3 more threads left to go per side before i can't turn the adjusters anymore to go up
, so that's an extra 1/2" right there unfortunatelly doing so will leave very little droop in the shock shaft for the CO's to operate optimally.