Quote Originally Posted by Z3_GoCar View Post
Two 1/2" grade 8 bolts per stack with grade 8 washers, the largest stack is five 10lb weights, the second is a 10lb and two 5lb'ers. So what additional reinforcement should I use maybe some 1/8" plate?
Yes - or at least 1/16" When I used to have weigh in my car (200 lb. or so) I used a rectangular plate that was about 8" x 3", with the two mounting holes about 5" apart (the weights were made about 10" x 6" and came from a stock car shop and were pre-drilled). Underneath the floor I used large and strong fender washers.

You don't want that s&*t coming loose when you roll the car!