How much added Horsepower?

[Blacknight]

I have my 1970 dodge charger with stock manifolds. I am thinking about getting a set of headers with a three inch exhaust how much added horsepower will that give me?

[Just 6T9 CHGR]

Headers will definitely give you some ponies....most say at least 50HP

The 3" exhaust might hurt performance unless your engine needs a 3" exhaust (high HP)

2.5" suffices for most street cars

[Musicman]

Headers are a big improvement, but you do need to get the right pipe diameter and runner length to work with your build...

[TexasStroker]

The exact gains will hinge around other aspects, but for the sake of being simple...it should be more than noticeable!  Similarly getting a nice full exhaust with an "H" crossover or "X" pipe will improve scavenging and I'm also going to bet your aftermarket mufflers (guessing you'd go dynomax) will keep the flow moving. 

"Sounds" like a nice upgrade 

If I remember correctly 2.5" pipes will suffice for up to 450HP, after that it is recommended to step up to 3" pipes.

[firefighter3931]

Like the others have said, headers make a big improvement. On a bone stock engine the gains should be in the 30-35 hp range and more as the engine combo gets stepped up. A good mandrel bent 2.5in x-pipe system with a free flowing muffler (Magnaflow/Ulraflow) will support up to 500hp. Beyond that threshold you should be looking at a full 3in system. 


Ron