Windage Tray Bolts

Hardened, flat on the main cap bolts.
Flat on the studs. To tighten down the tray to the studs, I'm not sure if nylon lock nuts would work well enough, perhaps double-nutted, or the crimped steel lock nuts. (I forgot the technical name.)

Doing it with the engine assembled does create a lot of problems. I wouldn't feel comfortable enough to try it.