FYI on K-frames
Mine k-Frame looked exactly same as first post. 1972 duster w/318.
Cleaned and rewelded mine, I also reinforced couple spot like steering box mount, lca mount etc.
Factory welds looked like my first MIG welds.
BUT if you think about it, mine car k member worked fine over 40 years with those crappy welds, not a single crack.
I have seen plenty machinery were factory welds failed after 10 years or less...