Switching from foot brake 727 to power glide with brake

I’ve seen this type swap on many cars that I would call marginal !! What I mean by that is a car that may or may not have enough horsepower to pull the power glide!! Generally speaking the cars I’ve seen with the numbers you have given actually slowed down in ET.. The cars just didn’t have the power to pull the power glide !! The higher horsepower cars seem to do really well with the swap !!