Why not? You just need bigger shims. My truck has 4* shims in it right now, all I did was spin them back around to get the right camber angle back.
I'm assuming Dana 35 here (I'm not positive the OP has a dana 35).. But According to SPC, these are the numbers you get from their shims. You can see you get a bunch less on a 4x4 versus a 4x2.
Here is the list of their cams and how much they move..
Series 2WD Adjust. 4WD Adjust
Part # Total Change Total Change
23181 .25 degree .20 degree
23182 .50 degree .40 degree
23183 .75 degree .60 degree
23184 1.00 degree .75 degree
23185 1.25 degree .90 degree
23186 1.50 degree 1.10 degree
23187 1.75 degree 1.25 degree
23188 2.00 degree 1.40 degree
23189 2.25 degree 1.60 degree
23190 2.50 degree 1.80 degree
23191 2.75 degree 2.00 degree
23192 3.00 degree 2.25 degree
23193 3.25 degree 2.50 degree
23194 3.50 degree 2.75 degree
23199 0.00 degree
What brand is your 4 degree cam? The 3.50/2.75 spc cam is already really thin on one side, I can't imagine how thin a 4 degree shim must be.
If you have a nice flat place to do the work, you can actually setup the Camber yourself (and toe). I use the SPC 91000 to setup Camber on our vehicles. Here is a shot of it when I was setting the alignment on the mustang.
Checking the Toe by
maniak_az, on Flickr
To make sure the suspension is not loaded I made my own camber plates. Its just 2 pieces of sheet metal (18x18) with bearing grease between them. I put one set under each front wheel. If you don't do that you can get some funky/wrong readings.
~Mark