Having had and driven all different power levels of the 427s if you just want a fast, reliable car to cruise around in, I wouldn't go over 450 horse. That will get you into trouble in a heartbeat and these cars aren't really heavy. I had one that put out over 500 horse and had it de-tuned down to around 425 horse as it was just to easy to break the tires loose. If you plan to race, that is another story. Also remember that the original Cobras just had 289sand the 427 ones put out about 485 horse, or that was what the competition ones were rated at. The Daytona Coupes which won the Championship had 289s which were rated at around 380/390 horse.
Ok, now all of the high horsepower worshipers can tell me how stupid I am.
Ron
