[sdbob]

I usually take engine completely apart before taking to shop.my labor,time is mine. Take out all plugs.I don't leave them ,freeze plugs,in block as I've seen many years ago hsppen.Then I use rifle brushes and clean as best as I can to get major dirt out.Then inspect bearings.Leave with rods and mains.Then take it to shop.I take apart new oil pump for contamination. Saw a large paper clip yrs ago in one so I make sure. I'm no machinist but I can clean and remove metal flash.Mine have been basic stock type engines.never have broken a stud like yours even bottle neck studs,pulled old press in out.Even in my SD stocker,seen 6400 a few times.I check installed height of springs before fire up.Sorry for your issues I had to redo my first SD engine luckily never fired.Lerned!! $$$$