1300 hp mercury comet brake failure crash

If the cars are equal weight, drag and etc. They will slow down the same because they are putting out the same amount of torque. The difference is how far you have to move the throttle to maintain speed when you encounter the grade.
Hmmm, by Your "logic" then, when My 'rolla engine & this supercharged BBC are both set to 2200rpm in identical cars of equal weight & dropped into gear they will simultaneously accelerate at identical rates & achieve 45mph at exactly the same time. Good luck with that.