Also, when the
oil pump shaft broke,your
oil pressure went to zero, you had NO
oil pressure,no oil pumping thru the engine...You can't get the other end of the oil pump shaft out from the top/distributor hole because it has a clip on it to keep this from happeneing, it can only come out from the bottom of the engine after you remove the oil pump.....Your gauge may not have been faulty,cause you had no oil pressure, how long did your drive it like this???? How the engine didn't sieze up is a miracle......
The rockers hitting the valve spring retainers is not good as is the marks on the rocker studs, this indicates all these parts are mismatched or installed wrong......something definetly out of wack in the valve trane geometry....
Leaking exhaust valve indicates bent valve, again not good.....I wouldn't go any further at this point without pulling the engine out and doing a complete teardown....if I rememebr right, you drove it some (maybe 10 miles) with zero oil pressure on the gauge??? that's not good, I'm betting your bearing while they didn't sieze are scarred up badly and would need replacing, and possibly need the crankshaft to be polished or turned........
all in all, not good, way too much wrong with this engine to go further without a teardown, IMHO of course......
David