This is what nhra rule book says about welding on roll bars and cages...
All 4130 chromoly tube welding must be done by
approved TIG heliarc process; mild steel welding must be done by
approved MIG wire feed or approved TIG heliarc process. Welding
must be free of slag and porosity. Any grinding of welds prohibited.
yeah..nobody ever grinds welds....lol
