Why do I keep breaking rocker arms?

Specs have been hard to track down, as the rebuild was subbed out to a supposed 'slant expert' in Texas (don't have the name). Texas built the engine with a 'performance' cam of unknown nature and I'm pretty sure everything else is stock.

I'll add pushrods to my 'more info needed' list.

#2 and #5 valve adjusters appear taller because those two valves are lower, which seems odd as one is intake and one is exhaust. I realize that this is a dumb question, but are the valves all supposed to be at the same height?