350 Exhaust Manifold differences

Hi everyone, doing some work and was looking to open up my exhaust flow a bit more with out adding headers or port work. Was curious if there is a difference in power from my stock exhaust manifold original 2bbl 350, or a tubbed style like on the GS or aftermarket options. I would like to know your thoughts and in put.
-Eric

 

Yes on a 300 Hp engine like a stock 350 you may only see 15 Hp gain with long tube headers. On a 500 Hp engine you would see a 30+ Hp gain.

 

and adding an X pipe can be 5 hp more and a quieter exhaust, especially with headers

 

Thanks! I actually already have an x pipe, think I’m gonna hood off on the headers for now.

 

And the sticker from the Flowmaster box is worth 10 hp if displayed prominently on the vehicle.

 

He asked about difference in manifolds, NOT about headers.

 

then take the part off that says "especially with headers"
X pipe with Flowmasters and Stock exhaust manifolds and 2 1/2" pipes... sounds good to me and the X pipe will take the excess noise out of the Flowmasters.
Put a flange just before the mufflers so it can come apart easier for future transmission removal.
then you can put that 10 hp sticker on
there are no differences in manifolds, ONLY in headers.

 

def gotta order some 10hp stickers!! haha. thanks, i appreciate the knowledge.

 

I'm not aware of any particular year exhaust manifolds that flow better but I'd be suprised if anyone has really looked very hard at it. I'm planning on getting a set ported for my next build. Not that you asked but there are also no shorty 350 headers available.

 

Stock 350 manifolds flow pretty decent for factory iron manifold’s, if you look at ‘em, they’re flowing, no sharp turns or bends, not as efficient as headers for max power but for near stock output they’re decent.