Broke rocker arm..

[DIRTYDOG427]

I have a sideoiler with about 2000 miles on it since it was redone...3800 total and after I changed the oil last Thursday and I took it out and broke the driver side rocker at the frount end of the shaft right next to the support.. This is a stock cam unit that was gone thru by a really reputable guy close to Dallas.. nothing fancy just 427 MR with stock cam and only dynoed at 400 HP or so..but it was tight and I could tell this as I felt it loosen up as I put the miles on-- as I got up around 1000 plus I got to feel it loosen up..
What parts(rocker shafts) are the best for my needs and What is the best way to determine if any other damage has occurred and since it's an old engine with old parts I don't plan on a big power thing..it's fast enough to kill me as it is.. in a Unique body with Jag 3:42 that was put together in 1992 or so.. When it was gone thru the engine builder told me the cam needed oversize bearings as I had driven it orginally about 1800 miles and at that point it begain to lose oil pressure rapidly between shifts...so I quit driving it and put it in the barn in 99 and just got it running this past summer.. I missed a lot of fun!! So anyway the builder said he had never seen a block like this one that had the cam tunnel too large.. He put oversize bearings in it and oil presssure has been 65-75 and solid-- depending on rpm..I made the mistake of not running a termostat in it this past summer.. but I caught it the first time I drove it in cold weather.. hell It wouldn't get to 140 degrees or so..but that was only one time.. and I put a 180 in it and new rad..it runs about 175 with airflow...
2 question--How to look for any collateral damage and appropiately strong new shafts..?? Thanks for the help !!