I've been reading some posts on headers ,i.e. short, long, loss of low end torque etc. Could someone explain the pros and cons of switching from factory exhaust manifolds to headers. Thanks

 

Factory manifolds suck. If you plan on doing any kind of performance mods, the exhaust needs to get out, if you can't get the exhaust out you just suffocate the engine(air+fuel in=boom that makes exhaust=gasses out). And the loss in low end torque with headers etc is either the result of too large a primary diamter(too big a header), too large a diameter collector/exhaust pipe or pipes that are too short for the setup(such as running open headers). A properly tuned exhaust system should flow without restriction AND provide the proper power pulsing(which is totally misunderstood and often called "back pressure" which it is NOT, backpressure=flow resistance=bad)

 

theres no cons about headers vs manifolds. headers is the #1 upgrade to an engine imo.

 

Then what type headers for a 289, 4v ,auto trans, and dual ehaust ?

 

Depends on what you plan to do later. I like Hookers, use the Competitions for mild mods, or if you plan on doing heavy mods in the future like heads, cam etc, then the Super Competition(they'll be a bit on the big side for a stock engine and won't make as good a power as the smaller Competitions, but will be better than stock and provide breathing room down the road)

 

Backpressure is not flow resistance. Flow resistance will increase backpressure, but the two are not the same. And yes, you do need some backpressure as it is what causes those exhaust pulses. Running open headers on a stock 289 results in essentially zero backpressureand, consequently, no exhaust pulses returning to help suck exhaust gases out of the chambers.

The problem is that backpressure is dynamic, so the higher the engine revs, the more backpressure increases. At the same time, the higher the rpm's, the less backpressure is needed to get the proper exhaust pulse timing. Therefore, a high-winding, high displacement engine is going to wanthigher flowingheaders and exhaust, whereas the same exhaust on a stock engine is going to actually decrease low-end torque and throttle response.

On a stock A code, I'd probably recommend hi-po manifolds or (preferably) tri-y's and 2-1/4" dual exhaust with an h-pipe. Full length heaers would work, but wouldn't be ideal unless you're planning to upgrade the engine in the near future

 

If there were a set of factory manifolds that performed like say, the Brand X ram horns, or the 289 Hipo exhaust that didn't interfere with my rack and pinion setup, I'd prefer the factory pieces

Although, the JBA's with the2 chamber flowmastersare pretty easy on the eyes& ears. And as far as the performance gain, ehh. I don't dog the crap out of my car 99% of the time, so I don't think I'd miss the performance loss.

 

So what you'r saying is that the $ spent really isn't worth it? My car runs very well as is, I'm not into making anymore upgrades, and not a drag racer.

 

If you like what you have then I wouldn't change it just for the sake of changing it unless I was just really bored and had too much spare $$ laying around for a new exhaust setup.

It's not like it's gonna blow your mind with the power gain from just a set of headers.

 

ive got a stock a code with tri y's and 2 1/4 tubing all the way back, no h or x pipe. dont really need it with a stocker.