That
Hemi got Edelbrock Heads?

Words by Richard Kratz photos
by Richard Kratz and Edelbrock, LLC

We can’t help but wonder if the devil is making a snowman down in hell because Edelbrock’s first ever Gen II Hemi cylinder head is in production now. We’ve heard various stories about why Vic Edelbrock decided not to make cylinder heads for the famous Mopar Elephant engine, but we have no idea if any of them are true. But that’s all in the past now and Edelbrock is celebrating the 50th anniversary of the Elephant in the best way possible, with new parts for the Mopar nation. Their new Victor Jr. CNC Cylinder Heads for Gen II Chrysler Hemi’s that make 40 more ponies than the heads available from Mopar are available now.

We went to Edelbrock’s manufacturing facility in Torrance, CA to see the heads in production for ourselves. We talked with Matt Gamble, the Edelbrock design engineer who headed the design project and he walked us through the process of designing and producing these heads. Matt was hired by Edelbrock not long before this project started and the young engineer was given the Hemi head project as his first assignment. But Matt is a car person, as are all the folks we know at Edelbrock, and he understood the gravity of his task. And Matt had plenty of design and engineering talent at Edelbrock supporting him throughout.

So what does Edelbrock imbue the new heads with to gain that 40 horsepower—and to our eyes the potential for more? Matt found room to improve the exhaust valve angle from the factory 23 degrees to a more optimal 21.5, thus creating room to enlarge the intake valve from the stock 2.250 inches to 2.320 inches. To take full advantage of the increased flow coming into the cylinder, Edelbrock presses a .100 inch wall brass tube into the exhaust pushrod holes—these passages intrude into the intake port in the Hemi engine. These tubes are much thinner than standard pushrod holes that are cast into the head could possibly be—you just can’t cast aluminum down to .100 inches thick on cylinder heads. The resulting reduction in port obstruction with the pressed-in tube allows more air to enter the cylinder.

The process of design and production starts with CAD-CAM on a computer, moves to a 3D printed flow study prototype, then proceeds to the foundry for the first metal casting. The raw casting is cut up and closely studied. Finally, a prototype casting is made and machined and then it too is cut up and closely inspected. Lessons may be learned at any of these steps and changes made as required.

Edelbrock is a very vertical manufacturing company; they own their foundry in San Jacinto, CA. All steps of the design, casting and machining process are done in-house by Edelbrock to assure complete control of manufacturing and quality standards.

The results speak for themselves on the Victor Jr. Hemi heads. The dyno doesn’t lie as they say and these heads make 40 horsepower more than Mopar catalog heads, right out of the box. And from what we saw in person, in our opinion it looks like there’s a lot of meat around those valves and in critical parts of those ports. We’d bet it will be pretty easy to find more ponies still in that aluminum in the ports and around the valves. Follow along with the photos to see the design and manufacturing process and view the dyno charts.