Magnum 300 crate engine - how should it go when tuned up right?

So, those magnum engines are no longer available?

They have not been available from FCA for a few years now. They are trying to switch over to Gen3 Hemi only. Plenty of Magum engines available in wrecking yards though, and lots of good ways to build off of one.
MRGTX has a decent head start with his 300 horsepower version. Make sure it's mechanically sound, then do some bolt-ons.