Windage Tray Installation?

Better be some thick washers, the difference in main cap height from 318 to 340/360 is @ 5/16".
Even if the washers are 5/16" thick, I feel that the 318 bolts wouldn't have the engagement in the threads to support the high torque load of the main cap bolts.

I'm betting MP switched vendors on this setup and they added the washers for aiding in torquing, as most A.M. companies do with high grade, high torque bolts.

MP is continuing to sag further and further down in quality and sensibility, I see.

Mark.