there are some measurements for the boxes on here above , or moparts. i think i used 1/8 steel .
i started with Weld 15 x 8 with 4.5 back space with 28 x 11.5 ET streets on mine -but that was before i moved in the leafs
right now with springs moved in and mini-tub , i have 15 x 10 welds with 7.5" bs , i think........... id have to go get my measurement book out. its in the garage and its Elevndy billion degrees below zero outside tonight....
