are shumacker headers restrictive?

I have ran the Schumacker headers down the track alot with mufflers on. If I would take the mufflers off, I know I can run in the 11s. Thats not to bad for headers that do not flow as good as TTI's.
veeery pretty car there! what spec heads/cam and carb you got? bet you notice a difference in weight with ali heads on:cheers: