340 issue after camshaft change

Pedestal rocker bolts can break with an aggressive cam, strong valve springs and the aggressive driving that goes with the previous two. That is the reason the OP has 7/16 7/16 studs. Adjustable push rods and lash caps get you back to the same situation this started with.
The OP needs to go through the motions of pull the intake off to visually check lifter status regarding off base circle and plunger travel position in the lifter bodies when the valves are on the base circle. With the intake off and a piston at TDC, it is easy to verify if it or its running mate are on the base circle. Those lifters will be lower than the running mate which will be on overlap and both lifters will be raised a bit. If the lifter bodies are both low but the valves are off their seats, back the adjustment off to get clearance like a solid lifter cam and then do the one finger zero lashpoint adjust. Then tighten down the adjuster nut 1/4 to 1/2 turn to set the plunger part way down in its travel.
Working with running mates and adjusting the cylinder at TDC firing has always worked for me.
You want sensitive adjustment, try 12V or 16V Detroit Diesel timing that uses timing pins of various lengths for different injectors, or a 2300 Cummins V12 with Top Stop injectors.

I get it. I said in post 2 to pull the intake and front cover off and see what the heck is going on. Clearly there’s some issues, and a bunch of really smart guys here have thrown a ton of info his way. I’d say the best thing would be the the OP to step back, regroup, read this thread, figure out if he’s got a LA motor or Magnum Motor, take a deep breath and pull the intake/ timing cover, lube / degrees the cam, pull the oil/ distributor shaft and get the thing set all back to zero...