engine block

There is only one way to find out. See if JB weld works, if not it's not difficult to find Silverado parts in scrapyards. With scrap metal prices being down you're likely to find a practically brand new block for cheap.

even if it wore through the block too?

I'm not a mechanic, just a do it your selfer. Guess you wont know till you try it.

I dont know how far down the water goes , but we use to grind the bottom of the cylinders in old small blocks to clear the rodes with a stroker kit. you might be able to grind a little bite more of where it rubbed to give it clearance. does it leak water? al