I have after market spring packs front and rear.
The rear axle has factory blocks on it that measure about 2.75" from the top of axle to top of blocks.
I measure 41.75" from ground to top of wheel arch on front
And 43.3" at the rear.

 

Measure just the blocks. Keep in mind there is a "block" that is curved around the axle on the bottom of the stack. This is welded to the axle. Dont count that. There will be blocks on top of that going to the springs. These are your lift-achieving blocks. Measure these.

 

I was under the impression that the blocks were stock. The lift I have in the rear was from the leaf pack



The top block measures 2"

 

As far as blocks go, you are completely stock. I dont know about your springs.

 

so if I was to get the traction bars with the lift block incorporated (4") I would remove those stock blocks and only gain another 2" considering there is 2" in the stock block