69 Z, Headers, VS Stock Manifold and Chambered

[JoeC]

Also try the lightest springs you can find in the carb and dist.

[JohnF]

I am by no means an expert but I have been playing with different set-ups on my Z/28 for almost 24 years. Here is what has worked for me. I run 72 jets on the primary side and 76 secondary side; yellow secondary spring and 25 squirter. Headers do make a difference! I currently run the 1 3/4" Hooker Super Comps, 2 1/4" pipe to a cross flow muffler, and 2" tail pipes. The only muffler, other than stock, that performs better (and is not too loud) is a DynoMax cross flow that is listed for the Buick GN. It is a bit shorter than stock but looks good under the car and seems to flow quite well. As far as timing advance, I run 10 to 12 initial and 36 total, all in by about 2200 rpm. I have never felt that going over 38 did much to create any more power. These are not racing modifications but work very well for me on the street. I have tried everything over the years including the original manifolds, etc. With the quick timing advance you will need good gas. You may want to visit the Camaro.net site and do a search under the name JohnZ. He has studied the original 30/30 cam and gives very detailed instructions on how it should be adjusted. Again, just my opinion, but this works very well on the street.

[NEW]

Hi,,
Basically what you people are saying is ::

72/73 jets front, 76- secondary,
timing 38-42, light springs,
carb light springs.
I∆ll try sometime during christmas or slightly in to the new year..

But back to the Chambered, good, or acceptable or just nice sound?

Smog system, anyone had trouble with this?,


THANKS Great info......

NEWs [img]/ubbthreads/images/icons/smile.gif[/img] [img]/ubbthreads/images/icons/grin.gif[/img]

[COPO PETE]

Chambered ain't bad, maybe Rob will chime in since he changed his. It is one of the best sounding though! I honestly think to get the best seat of the pants improvemnet is to put a M20 in it. With the M21 you will ring out first gear till your going about 50 MPH. With a M20, you will think you have woke up about 50 horse. I'll put my reputation on that!!!!...what ever my reputation is! [img]/ubbthreads/images/icons/confused.gif[/img]
Peter

[Chevy454]

Well, since you asked, Pete:

Factory chambered = Crap

It all depends on what your are going after. Nothing beats the sound of chambered, but the factory system is restrictive...and I mean WAY RESTRICTIVE! Flowmaster offers a 2.5" mandrel system which uses it's own "interpretation" of a transverse muffler, or Dynomax sells a really good transverse muffler that looks fairly close to stock and flows really well, but you'll have to bend the rest of the system yourself. BUT, if I was gonna put exhaust on something that won't be submitted to a tech inspection(!), I would buy the chambered system they offer for the new Camaros/Firebirds. The system is mandrel bent, but is a LOT bigger than the original chambered of the '60s. It supposedly adds power to the late model F-bodys, and is supposed to sound AWESOME, so it must be pretty good, because those late model guys won't buy ANYTHING without seeing what it did on a chassis dyno. That, to me, would be the best of both worlds: the sound and look of chambered, but built using today's technology.

As for tips for your Z-28...I have no idea about tuning it, but don't be afraid to REV THE PISS OUT OF IT! Don't worry, your ET's will thank you for it!

[NEW]

Hi,

In Norway they are very easy to deal with concerning tech inspections on cars older than 71. So i dont have to really worry abt. what i am doing concerning sound, etc..

The engine sound really nice and everything, but it is missing something, it could be that it is breathing to little.. Since it is an original car, and every thing is kept original i am really just not sure what to do..

But i think the exhaust, and the smog system does some strange things to it,,, I∆m not really sure, cause i havent run a 302 in any other form than this,

NEWs
thanks for the help, and if anyone else has any opinions........HIT ME [img]/ubbthreads/images/icons/smile.gif[/img]

[Keith Tedford]

The factory chambered exhaust has always had a reputation for being restrictive. If you drive on the highway much, the noise will quickly become annoying. I've run my spare M20 behind our L78 while having the original M21 rebuilt. Even with that engine I prefer the M20, especially in the city. What really helps a 302 to be drivable around town is the L79 cam.