Gosh, that in my opinion is kinda what they were designed to do. Except maybe scoot down to the local car show just a little bit faster than a stock head. And nothing says a savvy person couldn't do a considerable bit more with them.
Then in an attempt at a higher performance head they came out with the big port Super Stealth for some more oomph. But after we tested the Super Stealth it was obvious you could get as much flow from the standard Stealth and the Super Stealth became superfluous.
Now, God bless them, 440 Source will sell you the 240 & 270 Trick Flow heads for some 700+ horsepower potential.