[Hot Rod Reverend]

On the remaining two bolt holes, if you check a shop manual and the clip art or line art photos that show the block being mounted on an engine stand, you will see that those two threaded holes were used to bolt the block to the stand in a "side mount" configuration. My belief as to why would be so that both front and rear access (to put bearings, seals, the flywheel, the dampener, etc) could be had if you mounted the block on the side to a stand. If I had my manual here at the office I would snap a photo...sorry.