You have a Windsor. Windsor made truck engines; Romeo car engines. But because of a fire at the Romeo plant, 99-00 Mustang GTs received Windsor motors. Some engine builders say the Windsor is stronger than the Romeo and Procharger recommended in their 2007 catalog up to 12# of boost on a 99-00 Windsor but only 8# boost on a 01-04 Romeo. The Windsor has 13/14 valve cover bolts and an 8-bolt crank. The Romeo 11 valve cover bolts and a 6 bolt crank. I once heard that the cast rods and pistons were a little stronger on the 99-00 because the casting method was changed in 01, but I've not been able to verify that. The Windsor heads have a problem with the spark plugs stripping out, but this can be fixed with a heliocoil. Almost everyone recommend a maximum of 400-425 rwhp on both the Romeo and Windsor motors. 425 rwhp is approximately 500 hp at the crank. A supercharger and some complimentary mods is all it takes to get there.