A sure way to tell is to look at the front of the block, far right side, almost even with the height of the
oil filter adapter, approximately 3 inches in from the right edge of the block you will see either a 3/8" npt pipe plug or an unplugged hole. This hole was drilled into the "hump" on the side at the factory on SO blocks to open up the side oiling channels that were cast into the SO block.This hole should be plugged.
The shot below is from the lifter valley, you should see this stamped in the center of the valley.
Look at the bottom of the block below the freeze plugs, you will see two silver plugs screwed into the "hump" that runs along the side of the block. That hump is an
oil passage that is unique to a side oiler. Below that on the lower edge of the block you will see a couple of bolt heads screwed into the side of the block, those bolts secure the main bearing caps, commonly called 'cross bolted mains.
