I want to swap my 3.8 for a 4.6 dohc. I am looking at the mark 8 4.6 since it has aluminum block, and that is a lot lighter than the iron blocks of the cobra. So, is it possible to drop the mark 8 engine into my car? I know I need a wiring harness, and ecu, but is there anything I need to change, or do? I'm not sure of the laws here in PA, but can I put an older engine into my 99 legally with emission tests?