Looking for a little advice/help. I'm installing new main bearings on my '49 Chevy 3100 1/2 ton with 216 engine but have encountered a "small" problem. Three of the lock washers used to secure the main bearing caps were broken when I disassembled. These are hardened split washers but they have a slight crown that matches the scooped out landing of the cap - unlike a typical flat style washer. I'm hesitant to replace these with a typical split washer because of how the pressure is distributed onto the cap surface. The ID is 0.48", OD is 0.83", thickness at outer perimeter is 0.085", and inner perimeter thickness is 0.12". Anybody know why this type of washer is used and who or where I can find replacements?

49 Truck Nut