thanks jkaylor!
some progress, mocking up:
welded in the "boxing" on the front end and tack welded the cross member where it needs to be and the top hats. bolted everything together to see just how low it will be.
hope i am clear with this...
the bottom of the running board supports are 13" off the ground (trucks on jack stands obviously) the actual running board bottom is 1/2" higher or so.
the center of the spindle when fully raised (slammed) is 26-1/2"; so 26-1/2" minus the 13" = 13-1/2" times 2 = 27" tires to lay running board supports on the ground. that sounds correct.
i checked the suspension travel with and without the airbag, its the same. it seems that the balljoint has no more travel, causing the suspension to stop. there are about 5" of travel from full slam to raised, again the balljoint seems to bind stopping the travel. i have set the upper control arms "in" towards the motor on the adjustable slots, this gave me 1-1/2" or so more drop than with them all the way "out".
so, 205/75R15 tires are about 27".
any suggestions before i go in and fully weld everything?
Yaril