I ran a couple of 400's in stock cars 20 some years ago. Great engines, lots of cheap horsepower. They were tougher to keep cool than a 350 in that application, and they were less forgiving of high RPM's due to the longer stroke. I saw plenty of them get blown up with guys running stock bottom ends at 7000 plus RPM.

If I found one with 80,000 miles for $650, I would jump on it.