look what happened

RustyRatRod said
That's not too much torque. That's metal rot.

Nat said
when things hooked up well ,only thing that held things together was the sway bar . car has frame connectors and cheater slicks . drove it 30 miles to the shop in that condition , drove slow , real slow View attachment 1715546893

I'm not seeing rust there, that looks like metal fatigue. With that shiny new nut and bolt, I'd suspect that the old fastener was loose/missing and allowed that area to flex on the upper bolt. I'm just guessing from here. Good Luck, make sure it gets welded and gusseted. You may want to invest in some torque boxes as well. .02