1986 Chevy G30 w/ 200k miles.

After confirming there was nothing wrong with left bank of cylinders, removed rocker cover on right back of cylinders to see whether a collapsed lifter was causing an exhaust valve not to open (see previous thread here: http://www.thedieselpageforums.com/t...ad.php?t=36159) and discovered the #2 and #4 rocker shaft was broken at the #2 cylinder bolt, and the #4 cylinder rocker shaft bolt was broken. Lifter pieces can be seen in the pushrod gallery. The #2 cylinder pushrods are nowhere in sight.

We're trying to figure out:
1. Where my muh****in pushrods?
2. What else might be broken/damaged (cam, pushrods, valves, piston?)
3. What was the failure mode/what broke first/how do we prevent it from happening again?
4. How do we fix it?

-Joe and Christy