well i've started saving up for a headswap, new intake and new cam, and was just wondering if anyone knew of the legalities of these sort of upgrades in CA. also i've been considering going with a built 4.6 from a performance company or swapping in a pi motor or even a 5.4 sohc rather than working with my current block, but wasn't too sure of legal it would be? so yea, what are my options? all i know is that the engine must be of the same year or newer and must have been used on a CA emissions legal vehicle. so does his rule out crate engines?