At B&D Racing...they take 03-04 cobra motors with stock internals, stock block, stock heads, stock cams....and i've seen them get as much as 640RWHP...
they did an 07 shelby....put an exhaust, intake and a dyno tune and had it at 530RWHP...then they changed the supercharger pulley and put in 4.10 gears and they retuned it, but when they went to run a dyno pull for peak power...the car lost traction on the dyno so they couldnt get a reading...
i dont know if the 08 GT500KR comes stock with 550RWHP, but it wouldnt take much $$ to get it there thats a fact...
these modular fords with double overhead cams and superchargers are super cars
for the 07 GT/CS owners....heres some info about your 4.6L SOHC 3V motors..
B&D puts vortec and various other superchargers on that engine with exhaust and tuning mods, etc....the mustangs they put on the dyno survive if they make less than 400 Torque at the wheels....the few mustang they have worked on that did not survive on the dyno, spun two rods at 5000rpm and made just over 400RW Torque
the 3V internals are not forged steel like the 03-04 cobras...you cannot get over 400 RW torque out of the stock shortblocks without them failing
what B&D does is rebuild the bottom end of the 3 Valve motors and re-use the top end and add a blower...and the SOHC 3V heads are pretty damn good too, they have gotten over 600RWHP but it takes about $20 grand because of the shortblock needing to get redone also...
...if you want your 07 GT/CS to compete with a 07, 08 shelby, when you redo your shortblock to forged internals...go with a 4.6L--->5.0L stroker and add your blower...$25k later you'll have over 600RWHP
