Just to poke fun and further edu-ma-kate the masses. Why is there different size of valve reliefs in different blocks? I would chalk it up to whom ever was doing the notching on the block that day. Any input would be appreciated. I haven't sized them myself but one is nearly twice as big as the other. Lets not get into how that will drop the compression by 1 or two. More interested in why they did it to different blocks. These blocks were cast 3 years apart.