I am going to go look at a stock bore 400 block 817 casting it is a bare block with main caps, 2 bolt main. The guy wants $200 for it does anyone have an idea what the going rate for these blocks are?

 

I would have it checked for cracks and bore taper before you give him any money, unless you know the guy. $200 is about right but always try to talk him down, thats the fun of the barter game

 

I looked at it today it looks ok needs decked I have my doubts its a stock bore only one cylinder had any kind of a ridge on it. I stopped by the machine shop prior to seeing the block he said the same thing as you except he also said to sonic test the wall thickness in the block because alot are way to thin. I told theseller I would want to have it magged and checked first and he said another guy iscoming to look at it this week .. I have a 350 block allready bored I am just going to do a 383 with vortec heads for a street car with it.. We have a 406 already built for the drag car so it would have been just a spare anyhow

 

I would not buy anything if the seller wont let you have it checked out first