You can alter the valve lash by a couple thousandths in either direction as a tuning or comfort aid but you don't want to vary it too much - learn to love the sound of solid lifters. If they are factory rockers that have not been refurbished, wear will prevent accurately setting the lash with feeler a gauge, in which case, this method is best to use:
http://www.y-blocksforever.com/tech/html/valvelash.htmlFor a quick check of the rocker arms, give them a twist side to side. If you can detect any movement, then they are probably worn. You can also loosen the adjusters and use a mirror to take a look at the valve contact pad. Sometimes you can slide all but the end rockers away from the pushrod and flip it most of the way around to see without a mirror. If signs of wear are found, the only way to truly evaluate is to disassemble the shafts for measurements.
I don't think there is a way to check valve stems without disassembling the heads. The compression numbers are low. A compression test needs to be done with the throttle held wide open. Did you do that? If not, then that will explain the low numbers.
The pump arm may have been damaged because of incorrect installation. Maybe installed crooked and then forced into place by tightening the bolts.
Now to figure out why the 2-4s wouldn't idle correctly.
Lawrenceville, GA