Why does my clutch linkage keep breaking?

[Swar]

Over the 10 years I've owned this truck, I have had numerous problems with my manual clutch linkage.

I had recently upgraded to heim joint linkage I purchased from LMC.
First thing that broke was the little wedge nut that sits in the groove on the fork, snapped in two.

After that, the bottom push rod snapped where it pushes on the clutch fork.
So I put the old rod back in.

The stock clutch rod just snapped this morning, in the same place, where it meets the clutch fork.

What could be going on here? Has anyone had the same problem?
Take note, there's a pattern here, they both broke first thing in the morning, in cool weather.
Could the exhaust heat be weakening the metal? The header runs right under it.

It's a very worked 350, 4 speed with a Centerforce stage 2 clutch, so the clutch pedal is pretty stiff.