Everything that I have read about the vortec heads says that they have an efficient combustion chamber design. If this is true, than it would make sense that combustion would be more complete (as compared to mid seventies "smog" heads) and thus, emissions would be lower. I know that they would be an improvement performance wise, but don't know if it would noticable affect emissions. My car is carbureted by the way. Thanks for any help.
Mike

 

Since they dont have EGR passages, you'd be increasing your NOX emissions.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

But decreasing HC emissions

and you are right, the chambers are very efficient and in actuality, the more efficient the chamber the less NOX so you might produce the same amount of NOx as some older heads with egr

see www.TheOldOne.com for more details on how important an efficient combustion chamber is, the guy that runs that page is responsible for alot of the "fast burn" technology you are seeing now and some of the piston & head combos detailed on his site generated egt numbers like around 800 degrees whereas a standard head will push like 1200-1500

So, if the chamber is really efficient it can reduce HC as well as Nox(a byproduct of heat)

[This message has been edited by Pablo (edited November 22, 2000).]

 

Well right now, I am running old style heads with no EGR. I used a block off plate and had it tested just to see if it would pass. NOx was no problem, HC was a problem. It took a little creative tuning to make the car pass, but it did pass. No computer or anything. So it sounds like a win-win situation to me. I will check out that page and maybe get around to a swap in the spring. Thanks

 

Dont forget the Vortec heads have a unique bolt pattern, so you need a new intake manifold, or get them redrilled.