No, no, no, do not weld the running board mounting brackets to any part of the frame!
All I did was add two triangle gussets, one on each side of the outboard mounting tab locations which are bent 90 degrees on the mounting plate kit going from vertical to horizontal that will bolt to the body mounting studs sticking down at the front and rear of the running boards.
That stud is the body mounting stud to the frame wing mount sticking outboard of the frame.
A not of caution, adding the running board metal thickness to the body mounting studs does not leave any stud sticking out for the fiber lock nuts to really do their locking action. Thread locker a good suggestion applied to those threads and nuts.
This frame wing mount is located right by the front suspension radius arm rubber suspension pivot location. Same at the rear mounting of the running boards to the frame.
Going inboard on the running board's vertical mounting plate app four inches and slightly above the radius arm rubber location there will be a hole to bolt the vertical plate to the frame which is also the mounting location of the radius arm to the frame. The bolt hole on the frame as well the one on the running board bracket is too sloppy of a fit using the bolts supplied in the kit. I drilled both out for a snug fit on the shank of a fine threaded high strength aircraft bolt. I wanted to eliminate any mounting locations from shifting around and working loose.
After the gussets were Tig welded (one can Mig also), the running boards completely assembled, installed and aligned with the two small bolts connecting the running board's square tubing to the vertical mounting brackets. That square tube to outboard of the running boards is a 13" long lever, the inboard end of square tubing mounting bolts are only spaced 2" apart, ( my bad above reply stating 1 1/2" apart bolt spacing) see the multiplying leverage factor being applied to those two I recall only 1/4" or 5/16" bolts? When a 250 pound person stands on the boards your talking 2,500 plus pounds of searing action across those bolts. No matter how much you tighten those bolts including beyond the point of shearing them off they will slip at that joint period. This plus the sloppy fitting holes at this mounting location the running boards with bolts being snugged up you can lift to level position and down to sagging position up to 1 1/2" inches of travel. That sucks, looks crappy. Boards back up and level again don't step the boards again. Next make a weld pass 3" long between edge of the vertical plate to the square tubing. You'll now have solid mounted level and tight to the body running boards that can be easily unbolted and removed NOT WELDED to the frame. This just another example of cheap poorly designed accessories be it from LR or aftermarket accessory suppliers. Hope this helped, Carl.....~~=o&o>......