[gman26]

Am I better off using headers on my GTO clone? I got a 350 with an edelbrock performer manifold, carb and cam (278/288 dur-420/443 lift). I am planning on buying the Pypes Exhaust with X-pipe.
Do headers make that much difference? If so, which brand? I was looking at Summit Racing headers or Hooker.
Also, how are the ceramic coated headers better?

 

[lars]

Headers are quite a bit more effective than the stock manifolds - about 15 horsepower on most tests I've done. The stock Pontiac manifolds are actually quite restrictive. The Pontiac Ram Air manifolds are much better, but still not as good as tubular headers.

For a street car, the brand and tube length of the header is not that important - the key is to simply get the flow on the exhaust side. The cam you're using really needs some flow on the exhaust side, and any headers will achieve this.

Header installation on a Pontiac is not an enjoyable process. The header flange bolts are difficult to get to due to the angle of the exhaust ports and the tight wrap that the header pipes have to make to miss the crossmember. Make sure you get a set of header bolts with 6-point 3/8" heads so you can get an open-ended wrench on them. If you get bolts with heads bigger than 3/8", you won't be able to turn the bolts, and if you get 12-point bolts, you can't get an open ended wrench on them (which you have to do on the center bolts).

If price is not a problem, the Hooker SuperComp headers are top-notch. There are cheaper ones available, but you may need to do a little grinding on the bolt holes and a little hammer work on the tubes to get them to fit. Also be aware that any header on a GTO will reduce ground clearance a bit.

The ceramic coated headers have a couple of advantages:
1. They stay looking nice much longer than painted headers
2. They run cooler, keeping the heat in the tubes and out of your engine compartment. By keeping more heat inside the header tubes, exhaust gas velocity is maintained, so the headers have better scavanging characteristics.

Finally, make sure your cylinder heads have the end holes drilled and tapped for the header bolts - a lot of Pontiac heads do not have the holes for the end bolts, so you have to drill and tap them.

 

[lotaguts]

Why ??

I am wondering why GM did not put headers on them from the factory. If ford put headers on every old 5.0L rustang why cant GM do it especially on such a high output motor. The general wont shell out for anything cheap bastard.

 

[gman26]

That's what most people say... I think I'll go with Summit or Flowtech headers.
I have the engine out of the car so I can make sure the headers bolt up and install them when I put the motor back in.

 

[Verdoro 68]

Doug's Headers are also supposed to fit really well, better than Hooker's from what I hear. However, Pertronix recently bought them out so who knows if the quality and fit is the same as it was pre-buyout.

There's also a new Tri-Y headers by out there that look pretty nice - if you can get your hands on a set. More info at http://www.tribaltubes.com/.

I got tired of exhaust leaks, solenoid heat soak and bottoming out every time I went over a speed bump so I ditched my headers for Ram Air manifolds. Couldn't be happier. The only thing I really miss is the tinny header sound. IMO, for a street car that doesn't see a lot of track time, RA manifolds are the way to go.

 

[gman26]

will ram air manifolds fit a d-port pontiac 350? are they expensive?

 

[Verdoro 68]

Yes, they'll fit. They were originally used on D-port HO and RA engines. They run about as much as a good set of headers. I bought mine from Ram Air Restorations. I opted for the stock 2.25" outlet manifolds, but they do make them in 2.5" for a little extra flow.

Down sides are they weigh more than headers and, of course, you won't gain as much horsepower as you would from a good set of headers, but IMO the maintenance trade off is worth it. In addition you get more of a stock look and you don't have to re-route any factory lines that might be in the way (brake proportioning valve or auto transmission cooler lines). High Performance Pontiac did a header vs. RA manifold test a few years back and on a 389 there was a 12hp difference between headers and RA manifolds. On a 455 there was a about a 20hp difference. In all honesty, I didn't notice a performance difference on the street going from headers to manifolds. If I built my engine up a little more I might have.