Why do I keep breaking rocker arms?


Looks like a stepped bolt. The cups are close to 7/16" by my measure, and I measured almost all of them. Also a sh***y picture of adjuster and cup. Shoulda taken more of this one. I ran the engine but couldn't get a shot of the rockers and keep it from stalling out at the same time.

All of this is happening while I'm still driving the car. Despite this discussion it's a total blast to drive, and it's also, other than my work truck, my only vehicle. Since I'm being forced to drive like a gentleman, I'm appreciating how smooth and responsive the car is since the new distributor and tuneup.

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So the cups are 7/16" diameter at the top? The widest point?