are shumacker headers restrictive?

Are Schumaker headers restrictive? There are more than likely headers out there that will give better flow and give you that extra shave on your ET's down the quarter but consider this. If your running your car on the street and your concerned about a little better time then maybe you need to start jerking out the back seats and remove all the carpet and any other component that may weigh an ounce or so. I run em on my 440 73 Duster on the street and they provide as much fun...and more....than the law will allow but i get away with a lot more than i could ever pay for if you get my drift. Run em and have ya some fun.
Small Block