I just weighed the Megablock I have here. it is the version with the flat face in front of the oil pump. No machining has been done yet. With caps, 4.19 rough bore, it is 292 pounds. Boring to 4.500 will reduce it by 30 pounds using a weight of .259 pounds per cubic inch for cast iron and a 7" bore length. So there is a big variance in weight of these cast iron blocks.