yes, it is a dart block. but it is either a special dart block or it has had a lot of special machine work done to it. look at the lifter bores. notice how they are NOT straight inline like a normal block. the lifter bores apear to be cantered in there location. a special cam core would probably be needed for that setup also. 18 heads bolts instead on 10, now that is cool. the head gasket are probably special also. i wonder if that block uses the special large chrysler diameter lifters?