I didn't think the Dart block would weigh in that much more than the OEM block, they must have beefed them up quite a bit.........
This fall I'll probably get a Dart or the new Boss 302 block for my race car, right now I'm not far from 500 hp (331 cu in) and with my upgrades on the next race motor should be around 525 to 550 hp.......I don't think an OEM block will hold up to the kind of use/abuse it will get from me............
David