Metal Fatigue points in A bodies

I've repaired rear upper shock mounting points, K member cracks,
t-bar sockets that "let go", strut rod bushing hole blowouts, and
flapping tabs for forward upper-control arm mounts.
It seems that over 125,000 miles you just get these things.
I have 303,000 on a '71 Swinger with a 340, and 188,000 on a '65 Dart GT.
I've had good success with forming a piece of random steel to fit, then
drilling/tapping/bolting the bejeezus out of it.

Last friday my '65 GT cracked the 7 1/4 housing just outside the center member. I've never heard of this. There was no big bump or noise , just regular driving home from work. and suddenly there was this flubbety feeling.

What other areas have y'all had with stress fractures?

Also I've been using mid-80's Corvette shocks for years on the front.
You pull the botttom shaft, press in your old lower eye bushing, and it's a bolt-in. Anyone else? Then for the rears I've been using Ford 1/2 ton truck rear shocks. They're a bolt-in, too and really help with handling.