2000 magnum

Maybe the OP just thinks it’s slow, I mean it’s a 4x4 truck, there doesn’t have to be anything wrong with it to be called slow. I’d make certain the engine is worthy of any upgrade by doing a compression test and by using an accurate oil pressure gauge. Then just treat it like any other engine. Add RHS heads, bigger efi-capable cam, headers, intake, chip. What are the axle gearing ratios and tire size?