hey guys...I just wanted to know for street performance, is the stock manifold so restrictive with a mild motor like headers and mild cam ?:)

Steel intake manifolds are heavy and restricted to death if you are going with a set of headers and cam for the extra money go out and buy yourself a new aluminum intake it will lighten the motor up i mean a 50 pound intake compare to a 17 pound intake throttle response will be alot better.Eldebrock carries nice intake manifolds Performer rpm is a good intake or the airgap can't go wrong with these intakes hope this helps you some.

From what I've found over the years, you won't notice much difference on a mild motor between a factory cast iron manifold and an aftermarket aluminum one, unless the factory iron has EGR. EGR takes up space needed for good flowing runners and passages. If you take a non-EGR factory iron manifold and a non-EGR aluminum one, and compare sizes of passages, you will find that there isn't much difference. And, 30 extra pounds isn't going to make much difference in a 4000# car.
Remember, some really good factory motors used cast iron manifolds. A couple of good examples are the 1968 L79 327/350hp, and the 1970 L46 350/350hp engines.

Gary, you sure the 327/350 had the iron intake. One of my favorite engines but.....

http://images.andale.com/f2/129/117/19162015/2006/10/5/5915c.jpg

Gary, you sure the 327/350 had the iron intake. One of my favorite engines but.....

The 65-67 L79 used an aluminum intake and a Holley carb. The 68 L79 used a cast iron intake and a Quadrajet carb.

It's a known fact that a stock cast-iron Q-Jet like my '67 had on it new is HARD to beat from idle to about 34 to 3600 rpm!!!

And it will go above 6,000 too, but not as good as a Holley 300-36 or an E-brock RPM.. He, He!! 7,500 on my old junk301!!!

And that said, you will be hard pressed to beat a GOOD stock Q-Jet too on a mild motor!!

And I will say that if your engine is up to like 9.5 to 10 to 1 CR and that you use NO MORE than a CC 268HE or a Crane/Cam Dynamics 272/272 Energizer hy-cam, an E-brock RPM or the old Holley 300-36 dual plane intake and a 600cfm, 1850 Holley carb along with a cheap set of 1.625" dia., 4-tube long headers and a free flowing exhaust, your motor will wake right up!

pdq67

thanks all for the nice peice of advice:) I got it...