450-500HP 360?

Here's a 448hp 360 magnum
How to Add 129hp to a 5.9l Mopar Magnum - Engine Buldup - Hot Rod Magazine

Here's a slight destroked 771hp 360
LA Small-Block Kicking Some LS Butt on the Dyno

Here's a 510hp 360
371ci Mopar Small Block - Popular Hot Rodding Magazine

I'd say 10.5cr trickflow heads 240 ish cam will put you in your range.