From my experience, the first windage trays were used in 340's. Direct Connection sold a kit for use it in a 273 and 318. Since the 273 and 318 main caps are shorter, they needed two .125 thick 1/2 in washers per 340 bolt to get the tray in the same relation to the crank and same thread engagement as a 340. I've tried using two .12 thick washers under the bolts, but the tray bottomed on the block rails. The first Direct Connection bolt kit I bought actually had the ground 426 hemi main washers in it. When the High Performance 360 came out, there was a dedicated 360 windage tray that used the 340 bolts without washers, since the main caps are the same hight as a 340. Later they got the bright idea that if the slotted the attaching holes they could use the same windage tray for the 273, 318, 340, and 360. I'm guessing when the 318's became a Police package they changed the windage tray and finally made the shorter main bolts for the 318. Thanks
@Oldmanmopar!
