What kind of HP gains do you guys see once putting on your headers? Im talking about mostly stock cars, just boltons. Has anyone dynoed their car after? If so what kind of headers did you have?

 

I have seen 1-2 tenths improvement at the 1/4mile track with headers. One time I went from long tubes to shorty headers and lost 2 tenths. That was on a scarab 240Z

 

I went from 13.3 to 12.84 + 2mps with my longtubes and some practice.

 

I've heard 20 - 30 hp is possible depending on what brand you choose. Long tubes are best. Shorties are about as good as the stock manifolds. Mids are a little better than stock.

 

i got 23 rwhp from my flp longtubes

 

I gained 30 rwhp from MACs with cats and a LS6 intake on a stock Z28. Figure at least 1/2 was from the headers. I now have Hooker LTs, but put them on with heads/cam, so I can't give a difference between mids and long tubes.