I had the idea to trade something for a 1999 mustang GT that has 168,000 miles on the orginal motor.. now i was going to do this trade and probably rip that out and put in a new cobra motor.. would the car still be bad?
Is the motor the only thing that could go wrong with a car? Of course not, right? I'd especially worry about the rest of the drivetrain if you're thinking about pumping an EXTRA 140 ponies through it. If you do this, plan on replacing the tranny and the rear end . . . soon. it'll also be tough on the exhaust system, it might be worth noting here, the exhaust on that car costs a small fortune. The catalytic converter is in an "x" pipe that contains two resonators and two cats that all have to be replaced as an assembly. It's over a grand just to get that "x" pipe replaced.
Then you've still got the unrelated parts that will go bad on an old Ford. Electric windows, radio, power seats . . .
After it's all said and done it would have been cheaper to get an '03 cobra with 50,000 miles. Plus you get the independent rear suspension and massively upgraded interior that GT's so badly needed.
In modern cars 168K miles is not high mileage. Back when I wore bell-bottoms and had hair down to my shoulders - heck, when I had hair - engines lasted 100K miles if treated well. Starting in the late '70s or the '80s several major advancements in engine technology changed all that. Now any decently maintained and treated engine will last the life of the vehicle and beyond. I usually figure engines deserve some serious consideration when they reach 300K miles. Unless the car was neglected - in which case you really don't want it, trust me - the engine is probably in better shape than most of the rest of the car.