If you want 7000 rpm very often with an LA or Magnum based engine, then get a good forged crank. Once you are buying a new crank, why not go bigger.
If 400-450 horsepower is the goal, especially at 6500 rpm and less, factory cast cranks can live a long happy life.
The friction and drag thoughts are not an issue with a 4" stroke Mopar small block. Getting it to rev quick has more to do with the combination of parts to make it breath, especially camshaft events.
Build Your Own 455HP Pump-Gas Magnum V8 For Around $4,000! - Hot Rod Network
