No doubt the GT500 will walk the 427R. The "427" is flywheel horsepower. Subtract 12-15% for driveline losses and you get the 365-375 rwhp quoted above. That's about what a stock '03/04 Cobra did...if not a smidge less.
All in all its a cool car though. It's a great time to be a Mustang fan. The options are amazing and we've never had such high HP options in the past.
As I understand it, Arbour88 is correct. We will slightly edge them out... all other things being equal.
And to ingram's point... good luck finding a stock Termie. I don't think many people went as nuts about the collectibility of those that we see on the Shelby, so most were modded without regard to future resale. There are some truly sick Cobra's out there....
This is funny this got posted today. I raced a 427R yesterday on the street going to the car show I went to. He pulled up on me Going about 80 and I knew what was up!!! We slowed to about 45 he gave the honk signal and we went for it. I jumped on it and from the start I was gone and he was more than 10 car lengths behind when I hit 110, maybe further. We have each other the thumbs up and he exited shortly after. I drove a 427 when I was shopping for my Shelby and they are not even in the same category as far as power and performance goes IMO. They are beautiful cats though, I really like the Swede seats and the interior.
I've owned, modded, and raced both. Stock for stock or mod for mod the GT500 is faster. My 427R had longtubes, upper and lower pulleys, and 4.10s (only 430rwhp) and was still 3 tenths slower than my 2012 GT500 with just a pulley and tune (11.98 to 11.70 same track both on DRs). I loved the 427R but the Eaton M90 is a turd. Instead of going bolt on crazy I should have shitcanned the M90 and put a better blower on it.
I had the good fortune of driving 3 of Fords finest all in one day recently so I can give a seat of the pants assessment. My cousin, who lives in Florida bought a 2013 BOSS 302 in Oklahoma with only 2500 miles. On his way back to FL he stopped in southern Illinois where I and his brother, who owns a used car lot, live. His brother had just bought a 08 Roush 427R at an auction so we drove the BOSS out to the car lot to check it out. I had driven a BOSS before but was still very impressed with what 444 HP would do. Stab the throttle on a BOSS and you better be ready to shift because they wind up so quick.
We drove the Roush and while it was fast I believe the BOSS would have blown it away in a drag race as I drove both cars 10 minutes apart. I let my cousin with the BOSS drive my 14 Shelby and needless to say he was amazed and left Illinois pondering the possibility of putting a blower on the BOSS. I will say this the Hurst equipped Roush shifted like a dream. The BOSS had the MGW shifter and I really couldn't tell any difference from my 14's shifter. If I were ever to change shifters in the Shelby it will be a Hurst like the Roush had.