Tapping frame rail for trac bar mounting?..

[camokid]

SO I am in the midst of building my new back half and the way I was going to do the trac bar isn't really working out well, but, I can tap the rail and it would line up great. I am thinking about just tapping the rail and building a double shear bracketfor the outer. My question is do I need to beef the rail with mor plate, or is the 3/16 rail gonna be enough to hold the threads?...

thanks for any help...
Jeff