I have zero rake now.

I will attach a picture but with the cap and everything I need in my truck my truck sits level at this point Attachment 567798
Cap and equipment inside the bed is probably about 1000lbs

My truck settled after this picture !

I am planning on getting this kit https://www.stage3motorsports.com/09...Shock-Kit.html

If I set the front to 2.25 I would need like 4 inches of rear lift correct?
From what I read a 3 inch block would only add 1.5 inches of rear lift

 

If it is level right now, then adding 2.25 to the front would mean you would need to add more than that to the back.
Honestly I would do an add a leaf and figure out how much that adds and to give you a little bit better weight support, and then add those bilsteins once you know what to set them on to keep your rake.

Also you can't go much beyond 1.5-2" of additional lift with those rear bilsteins.

 

https://www.airliftcompany.com/
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Add a leaf

 

load leveler shocks will lift the rear a couple of inches or more, gas shock with the coil spring around it. Napa sell them among other places, Monroe makes them.

 

This, I have bags on mine I put about 1500 pounds of stuff including the cap and 15-20 PSI in the bags gets it back to normal looking. That is with 960 pounds behind the rear wheels

 

Wow, I've yet to see a super cab FX2 with a 6.2L! Nice truck!

 

Probably it being from New Brunswick helped, when I was looking it was any color but black and I kept going back to that one because of the 6.2

 

do not air air shocks or any other spring shock to the truck, shock mounts are not designed to carry a load.