What happened to the oil pan spacer?

360 LA pans where they meet the half moon cutout at the rear of the block are smaller than the rest of the smallblocks.

My understanding is that Magnums are the same size either 5.2 or 5.9

so a 360LA has its own oil pan (body styles not included in this) and everything else can share? that weird. something to do with rear seal design or journal diameters?