FWIW I think we need to be careful comparing hp rated in net or gross.
I believe the crate 300hp engine is a gross rating....
The say, 2000 ram 5.9 240?HP is net rating....
Assuming the crate motor was installed with factory magnum exhaust manifolds, and the only real changes is an alum. aftermarket intake, small 4bbl. and electronic ignition, in reality, the hp is going to be much closer.