Replace headers with N33 exhaust manifold?

[ironhelix]

I'm doing a thorough refurb of my '72 z and one of the important goals is to reduce cabin noise. Therefore, I'm considering replacing the 6-2-1 headers on my 3.2l street motor with an N33 exhaust manifold I had on a previous engine.

The N33 manifold was recommended to me on the early '80's as an alternative to headers by Frank Leary (Frogline Racing). He said the N33 flowed well, is quieter than headers, and that it was designed to help compensate for performance losses due to stricter '73 emission standards. I still have the drawing somewhere that he drew to describe it to me.

Anyhow, I wanted to get your feedback on this idea.

Link to E30 and N33 manifold photos, if you're not familiar with the differences:

http://www.classiczcars.com/forums/attachments/help-me/36624d1276877869-exhaust-manifold-question-1971-240z-n33.jpg

Thanks for your help!

Dave IZCC#508

[Jeff G 78]

I added a header to my '78 many years ago, but retained the stock cold-end. I cannot tell any difference in sound inside or outside the car. Keep in mind that most people swap the cold-end when they add a header so that will drastically affect the interior noise levels.

[ironhelix]

I added a header to my '78 many years ago, but retained the stock cold-end. I cannot tell any difference in sound inside or outside the car. Keep in mind that most people swap the cold-end when they add a header so that will drastically affect the interior noise levels.

That's a very good point. My 2" exhaust system is actually pretty quiet with minimal/no resonance. I'll stick with the header for now and reaccess after the car's put back together. I'm redoing all of the insulation so that should make a difference.