Heads, intake, pushrods, rockers, cover the requirements. You can redrill the heads to accept an LA intake, someone on Moparts had a jig that got passed around years ago just for this. You may, or may not, need to replace the lifters for oil thru the pushrods, you will have to look and see to know.
LA valve covers can work on a Magnum head, just pay attention to fitment as they are not identical. Exhaust manifolds/headers should bolt up for the most part. If you have air injection manifolds you might have an issue there.

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Don't be the exception.