Engine swap questions

I'm looking to get 450 HP out of the Magnum. Does anyone know if this is attainable from the Magnum (5.2) with F.I. and still have good street manners? I'm not totally against a carb. Am I wasting my time...should I just try to find an "LA" block and start from scratch? I'm just not very familiar with the differences in the "LA" engines and the Magnum engines. I figured it would be less of a hassle to just buy a complete setup pulled from a wrecked vehicle so I wouldn't have to go searching for all the little things...brackets, pulleys, wiring, etc. Any help is greatly appreciated!!!