Better metallurgy in the blocks (nickel content) supposedly, better machining, higher compression ratio (stock vs stock) and fuel injection kept them from wearing rapidly. The stock pistons in a magnum are hypereutectic and the stock rods and crank hold up well to a serious beating. All good things for a “cam, heads, and intake” type build.
Edited to add;
Roller cams from the factory. Much easier to upgrade.