Why would replacing the spot welded flange with a solid weld retaining the factory radius bother anything? With a motor plate the front frame rails now have a tied member above and below the rail. The thinner cross section in the center (it is boxed) hasn't shown any point of failure over 750 passes of use.
Doug
1. if success is justified by number of non failures, then the Challenger was pretty successful, until launch #25.
2. Not sure if we are addressing the same concern here, mine was about removing/narrowing OEM K member flanges, and then replacing it with any weld, The spot welds are not the main issue, and with millions on the road with just spot welds, they themselves have a pretty good track record. Removing/narrowing the flanges is IMO like removing the flanges on an I beam, one can do it, but if always reduces strength/stiffness, And the outermost edge of a flange can in some cases contribute the greatest stiffness, by weight to the structure, meaning its the last place to start trimming normally.