UH Oh.

I probably wouldn't stick roller in it, that's for sure!

Think like this... the cam rotates clockwise the front of the engine seems to be to the right in the picture therefore... the thrust is opposite of the crack.
Maybe skip using any lifter that has a band at the top like some do...or grind away the cracked portion and have the one lifter bore bushed.

That block was exposed to the elements and probably had a puddle of water or something around or in that lifter bore and it rusted up bad..then somebody took a pic or something to break loose all the other rest while it was being cleaned and blasted at the shop and probably cracked it while prying away the loose bits. It was a core block from a machine shop maybe?