[WARPed]

Originally Posted by ho428

What aftermarket block is that. First time I've seen the backside of one, shows casting plugs in the deck area.
I assume that's done to use the dual bell bolt pattern?

This is a IA '1' block but the current IAII blocks look virtually the same setup. They do come with both bolt patterns and the rear "pads" just below the heads are there to drill & tap for a coolant feed in the back of the heads on a dry deck arrangement. I am sure the MR-1 blocks has all the same stuff back there but I have seen one in person.