Those hogshead lugs match the bolt lugs on the rear of the '26-'27 block.
Reason is to maintain the centerline of the 4th main and to assist that vibration and twist was minimized for reducing bent pans,.
For keeping the 4th main in alignment, shims are added to the mounting bolts to push the hogshead where it needs to be.
Those bolts also held straps to each side of the engine mounting flanges to the frame. Those straps resist twisting of the engine in the frame.