I painted the exhasut manifold of my 350, get a gasket from Remflex, new set of bolts and then (at last !) I thought to myself, why not put a header?
I saw some are not really expensive but what would this really brings to the car?
Car has a real nice noise, accelerate quite well. Then what would be the reason to use a header? Is there any? I would save some pounds though but what else...

 

Headers make more horsepower than stock exhaust manifolds ,Because they are more efficient and you can tune them to your purpose.Its just cheaper and quieter for the car companies to exhaust manifolds .Along with government regulations

 

I read that but is it really real? Anyone change it and notice any difference?

 

Headers by themselves will make a slight improvement in power and they will sound better but typically they are part of an overall performance package.
When you start adding other performance parts like an aftermarket high performance intake manifold and carburetor with a performance cam and maybe headwork or aftermarket performance heads,as well as other mods like higher compression pistons etc.etc. you must free up the exhaust flow,more air and fuel in needs more exhaust flow to get out.
In short they are a must on a performance build but can also be a slight improvement in power and fuel mileage on their own and many just add them for a deeper exhaust note than stock.
If you do add them I would spend the money for a good set for a couple of reasons,for one they will fit better and last longer for another if you get stainless steel or ceramic coated they will look better and not rust.
Cheap headers will soon burn the paint off and start rusting,they may also have poor quality flanges that lead to exhaust leaks.

 

Thank you for this information. So I won't spend much there. Sound is quite good already and I don't want to spend too much on that alone for a marginal effect on power. The prices I found for cheap ones are fine but as you said I'd get just what I pay for. So we'll stay on heavy iron cast for now...

 

Probably a wise move if you are happy with the sound and the way it runs,manifolds should be fine and are less prone to problems like exhaust leaks and bolts coming loose.

 

A lot of it also depend on the design of the manifold. Some manifold are header like in design and some are not. Example the old stock 60's and 70's base model manifolds suck for flow.