Be a little patient as I don't know how many people will know the answer!
STR 2004. Acronyms: http://www.jaguarforums.com/forum/s-...-jaguar-78910/
If you would like the most accurate assistance, it is very helpful to place your vehicle information into your signature line, just look in your member control panel to set it up. Info like year, model, engine size, and other details like mileage can only aid in receiving more replies with the correct information. (thanks, h20boy!)
I've looked into the cylinder of the 4.2SC today. The pistons are dished, the heads are all the same for 4.2NA and 4.2SC, the only difference is the plug in the oil channel to VCT (which should be removed if the head is installed on NA engine).
I suppose that if you install the NA engine with supercharger the CR will be way to high, so the engine will ping all the time.
Wish you were closer to me, so we can exchange the engines