Ported Small Block Chevy Cast Iron Intake Manifolds

Stage 1 & Fully CNC Ported Cast Iron Small Block Chevy Intake Manifolds

Let’s face it, the stock cast iron intake manifolds were designed for street cars, which run from idle to about 3,500 rpm.  Well, on a race car, you are not running under 3,500 rpm.  That is main reason why you lose so much horsepower running stock manifolds.

So, if you are stuck running cast iron manifolds, the #1 thing you can do to small block Chevy is to modify the intake manifold. Period.

Stage 1 Ported:  A ported intake manifold that is modified as much as possible through the plenum area and the port opening.  These manifold receive 5 hours of CNC machining followed by hand porting and shot blasting to put some “texture” back into the ports.  Nothing on the outside of the manifold is altered.  Typical performance gain is 15 to 25 horsepower over a stock manifold.

Fully CNC Ported:  The Fully CNC Ported manifolds receive 7 hours of CNC machining, which includes the machining of four 2 1/2″ access holes in the manifold.  The access holes allow us to modify 100% of the manifold.  After the CNC work, the manifolds are hand ported, shot blasted and the 4 large access holes are sealed.  The result is typically a 30 to 45 horsepower gain and the manifold looks stock on the outside.  This is our best cast iron manifold.


 “Stage 1”  2 Barrel Intake
80% of the manifold is ported.    Typically, a 15 to 25 horsepower gain over a stock manifold.  Stage 1 Ported 4 barrel Q-jet manifold are also available.

Fully CNC Ported Q-Jet  100% of internal surfaces of manifold is modified resulting in the best cart iron intake money can buy.  Fully CNC Ported 2 barrel manifold is also available.

Our modifications combine to produce  horsepower gain and maintain that vital stock appearance. Compare for yourself with these dyno tests.

Have to run a more “stock appearing” intake manifold? We also have acid ported intakes.

Fully CNC Ported manifold after rough CNC machining.  The 4 access holes allow us to rework 100% of the internal surfaces of the manifold.



Stage 1 Ported Chevy Small Block cast iron 2 barrel intake manifold

Fully CNC Ported Chevy Small Block cast iron 2 barrel intake manifold

Stage 1 Ported Chevy Small Block cast iron Q-Jet 4 barrel intake manifold

Fully CNC Ported Chevy Small Block cast iron Q-Jet 4 barrel intake manifold

In the original form, the Chevy cast iron intakes were designed to run from idle to 3,500 rpm. However, on a race engine, the engine never sees anything less than 3,500 rpm on the track. This is the reason the stock intakes are so restrictive for a race application. As the dyno charts show, the addition of a ported cast iron Brzezinski intake will add horsepower to your engine from 3,500 to 7,000 rpm. If you are interested in performance below 3,500 rpm, such as for a tow vehicle, keep the intake stock. If winning races is your goal, get one of our modified intake manifolds.

Cylinder Head Design Form: Fill out our online cylinder head design form for a recommendation and pricing on a set of heads built specifically for your application. Also, here is a link to more detailed information on our Complete Cylinder Head Assemblies page.