OK, I want my car to be faster. (Who doesn't? )

I'm running the stock manifolds and 2 1/4" piping all the way back on a 305 TPI engine that is overbored slightly with a better-than-stock cam but is otherwise pretty much completely stock.

SO, my question is, would it be worth my while to invest in some nice headers and 3" piping all the way back? Will leaking be an issue? Would I see noticeable gains? Approximately how much HP should I gain (using a set of good quality headers)?

Answers to all of these questions would be MOST appreciated!

Thanks for your help as usual,
-AJ

 

Just so we are clear. Are you running totally stock exhaust? Manifolds, crappy y-pipe, single I pipe, crossflow muffler?
You say 2.25 all the way back. Are you running a custom dual exhaust? I don't think the single I pipe isn't 2.25 if it's stock--which is why '2.25 all the way back' makes me wonder what exactly you have.
Anyway, headers will give you more power even on a bone stock engine. If you are running a single exhaust, absolutely get the y-pipe for the headers--the stock y-pipe is not good at all. Compared to the stock exhaust: Headers, y-pipe, hiflow or no cat, 3 inch I pipe, good flowing muffler(not flowmaster IMO) you should feel a boost in power. A complete guess is at least 10hp from bone stock--probably more depending on what you have changed. Should also see better mileage and a much better sound

If it's done right it won't leak

 

I answer your question with a question...



Does a Bear crap in the woods?

 

Personally I got a 20hp gain at the rear from Edelbrock TES(headers and y pipe) and a high flow cat. At the time the only mods on my car included a Edelbrock 600cfm Carb, Edelbrock performer intake manifold, Hooker cat-back(mandrel 3" I think), 14" open air cleaner with KN filter. If I was you I would go with a set of headers, y pipe, high flow cat or non, and some nice 3" mandrel bent cat-back. With this setup depending on brands you should expect 15 HP at the rear and maybe 10-15Torque.

 

Definetly man! Headers are one of the best modifications you can do to a thirdgen. The exhaust is also a good start. Those are some of the first mods you'll do to you car to see a noticable power gain.

Leaking will not be an issue if the install is done right.

I'm unsure on the actual hp/tq gains you'll recieve, but like I said it'll definetly be a noticable difference. Good Luck

-Randy

 

Ok, I forgot to mention my flowmaster 40 series muffler and hi-flow cat.

Anyways, there's that too.

Thanks for the replies gentlemen! I'm definitely leaning more towards getting them installed.

-AJ

 

The horsepower gains dont sound like much , but when I still had the 305 tbi in my car I dropped .6 seconds of my quarter time when I installed my headers,deleted my cat , and put a cat back on. That was very impressive to me .