If you are sliding a 426 Gen-II HEMI under the hood of your hot rod, what better way to top it off, than with a dual-quad intake that not only looks cool, but can increase your Hemi’s power output!
There are only a handful of words used in the automotive hobby that are as instantly recognizable as the word HEMI. Originally, the HEMI engine displaced a cubic-inch size that was smaller than that of a small-block 350ci Chevrolet. Eventually, somebody got it wet, and it swelled to a factory-stock size of 426 cubic-inches. Now, the second generation HEMI is an icon, whose cubic dimensions are only hampered by the imagination.
The Edelbrock dual-quad Hemi intake is compatible with factory style cylinder heads, but has been optimized for use with Edelbrock’s Victor Jr. HEMI cylinder heads. If running EFI, the Victor EFI Fuel Rail Kit (PN; 3660), is also available, which will accommodate 60mm injectors.
As great as the HEMI engine is, you would think that there would be a lot of aftermarket parts available, and you would be right. So, if parts are already available, why would Edelbrock decide to invest the resources to build an intake for the Gen II HEMI, when there are already others on the market? Well, we wondered the same thing, so we talked to August Cederstrand of Edelbrock (he’s their resident Mopar guy), to find out why they made their new Gen II dual-quad HEMI intake.
Rod Authority: First off, why build it? Aren’t there other companies building Gen II Hemi intakes?
August Cederstrand: “Yes of course, there are several fine companies building intake manifolds for the Gen II 426ci HEMI. In 2014 we debuted our 426 Victor Jr. heads, it was only natural for us to develop our own manifold to complement those heads. Edelbrock is known for building some of the finest intake manifolds around. We always look to build something that other companies haven’t thought of, or something that really works a lot better than our competitors. We saw a niche for this manifold and it goes along with the heads quite nicely for its targeted group.”
RA: What makes the Edelbrock intake better than other HEMI intakes on the market?
Cederstrand: “We never walk into battle blind. We study our competitors, and look at the market trends to figure out what our customers are doing with their cars. Our goal with any manifold or part we make is that it has to work better and make more power than its direct competitor. We do extensive testing on the engine dyno with our manifolds, and that is only after many hours of computer modeling and reshaping to come up with the product you see today. We [Edelbrock] have 77 years of knowledge and experience, and the products are made in United States of America—in our own foundry, and machined at our own manufacturing facility, both in California, which are both ISO9001 rated facilities.”
When tested on a 528-inch Mopar Performance crate engine, it produced 656 horsepower and 618 lb-ft. of torque. It outperformed the closest competition by 35 horsepower and 5 lb-ft. of torque.
RA: What can the average street rodder with a Gen II HEMI in his car expect by using the Edelbrock intake?
Cederstrand: “He can expect to have an intake that is made to the same qualities of the highest degree as all of our intakes. He will bolt on an intake that will make more power than any of its direct competitors in the same design arena. He will also benefit from the latest thinking and improvements in manifold design and airflow science applied to this manifold. This isn’t a rehash of an old manifold that was designed decades ago by someone else, and then dusted off with a new name applied. This was a clean sheet of paper design with specific goals in mind.”
RA: Okay, so what were those goals?
Cederstrand: “The goals were that the intake had to make more power than our competitors, and while designing and building the manifold, it had to fit within the external dimensions of an OEM HEMI dual-quad manifold. It also had to be a good looking manifold. I think we nailed it on all counts.”
The intake is designed for use on all second generation 426-572 cubic-inch (1964-1971) HEMI engines. The Air Gap design helps keep the incoming fuel/air charge cooler and denser than that of the factory-style intake.
RA: If this intake is to replace the Mopar intake that is no longer available, have there been any updates or improvements?
Cederstrand: “The first design parameter that had to be met was that this manifold fit inside the stock design envelope. Meaning that when we designed this manifold, we [input into] CAD, the parameters of the OEM stock manifold over our manifold. It had to fit inside the OE parameters—dimensionally, this would lead us to the same height as a stock manifold, both front and rear. The carburetor placement is the same as a stock manifold, both fore and aft, which in turn allows the customer with his existing Mopar musclecar to use his stock air cleaner assembly and shut the hood. Let’s face it, a guy with a $100,000 HEMI Cuda doesn’t want to cut or modify this hood, so we made a manifold that fits without destroying the car, or having to fabricate non-stock looking pieces.”
Cederstrand (cont.): “Our manifold could most certainly be used as a stock replacement item. The factory dual-quad, dual plane manifold was limited at best. Arlen Vanke was made famous with his modifications to the plenum area of those manifolds in order to get more power out of them back in the day. Gen II 426 HEMIs are big air pumps, and guys are building bigger HEMIs than ever before.
We went with a dual quad design, because a lot of customers want dual quads since HEMIs came with them. We went with a single-plane design, because it moves more air than a dual plane. Best of all, we made it an Air-Gap style manifold to keep the runners away from the hot oil for a cooler, denser, intake air charge. Let’s not forget to mention that it also comes in carbureted and EFI versions, that way it is easier to modernize the 426 HEMI and bring it into the 21st century.”
The Edelbrock intake retains the stock Mopar Performance height and linkage spacing, and is available for carbureted (PN; 7524) and EFI (PN; 75245) applications.
RA: What type of engine would this intake be most at home on: highly modified, street modified, or mostly stock?
If mounting the ignition coil to the intake, this intake manifold requires the use of Edelbrock’s coil bracket (PN; 8079) when using OE style coils.
Cederstrand: “We designed this manifold to complement our heads first. Guys are building their own HEMI clones because factory originals are very expensive. So now, the next best thing is to build your own. So, why not build it bigger and better? Like our heads, a lot of customers are going to 4.5-inch-bore blocks from the aftermarket. It then becomes quite easy to build a 528, 540, or 572 cubic-inch street HEMI.
A fifty year old, stock dual quad, dual plane manifold will not flow the air needed to feed that machine. Hence we saw an opportunity to address that problem. They want it to look stock but make a ton of power.
So in reality, this intake would be at home on any 500+ cubic-inch street HEMI, and it will work on a hot 426 cubic-inch HEMI. I would say your highly modified or street modified customer would enjoy this manifold the most and receive the greatest benefit. These dual-quad HEMI intake manifolds are intended for use with 426-572 HEMI engines operating in the 2,500 to 6,500+ rpm range.