Its not 602 ci... A gm '602' motor is a 350 ci sealed crate race motor. At my local track you can run a crate 602 with a 4 barrel or an open engine with a 2 barrel. Crate motor is way cheaper of an option to go racing.
As for mopar power not really sure what would need to build. I know we run an open motor with a 500 cfm 2 barrel and was 485ish out of a 358 in dirt sportsmen 7000rpm. Turing the carb sideways and pushing it all the way to one side made 12 more horsepower on dyno. Motor cost close to 10k professional built vs 3400ish for a gm crate
