The reason this probes had about the same or more HP than the mustangs of this same period, (1st Gen only) was that the probe was planned on being the newest 'Stang.
ford heard rumors of other manufactures doing light small 4 cycl cars that would get good gas mileage but quick, so they used what they could and had mazda build them a motor and before you knew it they had the new mustang.
Then they showed it to the public, and they ripped ford a new you know what. so they took a book of names the already had trademarked and probe was it.
But its still got the zoom zoom in it, or at least mine does.