How to Choose an Intake Manifold
This is the big debate: single vs. double plane intake manifolds. It’s something that every builder has to deal with. What I used for my 454 is shown here. I’ll tell you a little about the engine first. I found a used 454 from a 1970s Chevy 3/4 ton truck. When I took the engine apart, I saw that it was marked “HI PERF” on the side of the block. This means that it was very good. Because I am a gear head, of course, my heart started to race when I saw this. Oil pan: I couldn’t get it off in time. A forged crank and 4-bolt mains made me happy. Score! The engine was very clean and had very little wear on it. It was a standard bore with small “peanut port” heads on it. A GM Goodwrench replacement crate motor came up when I ran the casting number. That’s what you’d expect, right? I was bored with it. 10/10 for main and rod bearings, 030 over with a mild dome piston. You’ll also need a good intake manifold to go with the aluminum heads you found. The search began.
How to Choose an Intake Manifold
Make sure you are honest with yourself about how and where you will drive your car when you choose an intake. There are two main rules. Most cars that are used on the street will be better off with a dual plane intake. A race car, drag race, circle track, and so on will be better off with a single plane intake. The dual-plane divides the runners into two groups so that fuel and air can be sent to specific ports in the firing order. When you drive at low RPMs, there is less back pressure in the plenum, which makes the engine run more smoothly. There is backpressure inside the plenum as the engine fires through the firing order because the plane feeds fuel and air to every port. It helps the fuel atomize inside the plenum when the RPM is high. At high RPMs, this type of intake is better, but at low RPMs, it makes it hard to idle. Also, most intake manifolds have a range of RPMs on them. The ranges on this page are based on a lot of research, so you can trust what each company rates their intake manifold at.
As soon as I had this information, I began my search. Dual-plane intake: I decided to go with a dual-plane intake because my sleeper is going to be used mostly on the street, but it will have a lead foot when the lights go off. I chose an Edelbrock RPM Air-Gap 2-R Intake, Rectangle Port, Big Block Chevy. My car had enough space under the hood to get the taller air gap, which makes the fuel mixture cooler and denser for more power. Because it has two planes, it has a 180-degree firing order. This makes it good for low-rpm driving because the single plane has a 90-degree firing order. A range of 1500 to 6500 RPMs is just right for the cam I chose.
There is one thing you need to know about this intake. It is not a true dual-plane design. a cut-out is found right below the carburetor in this plenum divider piece.
I think the cutout shown above may be one reason this intake is rated for 6500 RPM. I used Edelbrock’s Intake Manifold Bolt Set to put this intake on. They are made for Edelbrock manifolds and have a twelve-point reduced head for easy wrench access with a hardened washer. I torqued them to 25 Ft-Lbs. in the correct order from the instructions that came with them. Fel-pro is the gasket of choice for me, which is why I’m a little picky about them. For the gaskets, I used the Fel-Pro B/B Chevy Intake Manifold Gaskets, and then I added a little bit of black RTV silicone on each end. This intake was just what I was looking for because it was easy to fit and had a simple finish. It goes well with the aluminum heads and has a more aggressive look because of the air gaps. We need to find the right carb to finish it off.
