How come horsepower tv gained a very small amount of hp off a 70mm TB on a 97 stang?

[96_4.6]

Just wonering but they had a stock I think 97 or 98 I'm pretty sure it was an 97 mustang gt and its there project car that is DEAD stock minus the working mach ram air hood. Here in michigan we have this great show called horsepower TV on tnn!!! Anyways the only engine mod they made was the 70mm throttlebody and they dynoed it right in front of you and they gained up to the whopping 183 rear wheel horsepower, wow I think that was after the TB but they wouldnt put something on if they were going to lose horsepower cause there trying to get the most HP out of this thing, BTW they put longtubes, highflow h-pipe with cats and tuned it with superchip tuner and got up to 204 RWHP....grrrrrr but I think I'm gonna finally spend the 120 bucks to get a mac 70mm. might as well