Why do you have to hang leafs 1" forward and 2"down? Im going to build one but id like to get a better understanding first. 1st gen 4runner sas in progress.

 

I think it's because the allpro and trail gear springs are longer than stock . Also if you run bigger tires they will hit the fenders so you want to move the axle forward . The 2 inches down is for spring and steering arm clearance . When the front springs flex flat they come very close to the steering box pitman arm shaft . Also might help with castor angle. You could run less hanger drop and 1 or 2 inch taller spring . Just put bump stops so nothing hits .