Heavier block that can be bored out quite a bit. Forged crank.
Big downside is lack of aftermarket. Custom pistons are required if you want anything close to 10:1 Even stock cast iron 4bbl intakes fetch north of $500.
Mine is a beast. Just had Gary Pavlovich and GRC Machine work it over. It is a torque monster and pulls like a jet from 40mph. It has right at 500 miles on it so far. It's no stroker, but has no issue laying down rubber and putting a smile on my face.