cost of engine blocks

I would at least drop a bore gauge and see if they are standard bore or oversize. A clean standard bore 340 block will bring good money. I would say around $400-$500. Not sure on big block stuff. I have a couple 440's but I bought them so long ago. Same with all my 340's. I paid next to nothing for them 20 years ago. They were very hard to find even back then. I would say 340's are MUCH easier to find now with the internet.