To quote from the Dart site:

"Dart's new Special High Performance (SHP) small-block meets the need for an affordable, precision-machined cast-iron block with superior features. Designed for high-performance and heavy-duty applications producing up to 600 horsepower, the SHP block is the ideal starting point for hot rodders, drag racers, circle track competitors, off-roaders, and high-performance marine enthusiasts." unquote

This is a new block, Mains #2, 3, 4 are 4 bolt with splayed caps... Dart retails it for $1500, seen it other places for a bit less.........

Guess it depends on what you're planning on building, but this looks like a heck of a deal for me... Think chebbie sells one in their catalog for even a bit less???????