When Edelbrock first announced they had aluminum heads for Chevrolet’s 348 and 409 cubic-inch engine, we had some reservations about how enthusiasts might react. Let’s face it, while the 348ci and 409ci W-head engines are a great piece of history, they are such a small market when compared to the small- and big-block Chevy engine that we thought the market was too small to make the head viable. Seriously, the last time the engine was mass produced was 1965. So … it has been a few decades.
When 1965 came to an end, so did the reign of the the 409ci engine.
The Edelbrock head has been on the market for a couple of years now, and apparently, our reservations were misguided. We talked to “Smitty” Smith at Edelbrock, and when we asked why Edelbrock would build a head for this engine, he told us, “Primarily, because we kept getting customer requests at events and shows. After a while, we realized we were getting so many requests that we thought, maybe we should make them.”
The 348ci and 409ci engines hold a special place in Chevrolet hot roddere’s hearts, and with good reason.
A Head For All Reasons
These new heads were a great addition for hot rodders and even drag racers looking for a new cylinder head for this often-overlooked engine. That is because, until Edelbrock created this head, stock heads consisted of four versions: those used only on 348ci engines, heads specifically used on 409ci engines, heads that could be used on both engines, and finally, the rare, unobtainium Z11 heads.
The valves in original 348 and 409 cylinder heads are placed at an angle across the cylinder bores – much like those of a traditional big-block, instead of in a straight line through the length of the cylinder head. This arrangement provides several benefits. By positioning the intake valve closer to the intake manifold, and the exhaust valve closer to the outside of the block, these shorter routes for air flow increase performance.
A lot of people thought we were crazy to offer them, and I’ll share with you that we sell out every production run we make. “Smitty” Smith, Edelbrock Performance
Chevrolet’s offset placement of the valves was possible because of the deck angle on the 348 and 409 engine block. Traditional V8 engines utilize a 90-degree deck-to-bore angle, but the deck-to-bore angle on a W engine is a 74-degree angle.
Another unusual feature of the W engine cylinder head, is the lack of a combustion chamber. Unlike a conventional cylinder head that houses the combustion chamber, these engines have them as part of the cylinders. Since the block’s deck is at a 74-degree angle to the centerline of the cylinders, that, and the design of the engine’s pistons created a combustion chamber within each cylinder wall. This design resulted in an engine with a lot of low-end torque that made these engines perfect for use in heavy cars and trucks.
While the 409ci engine seems to get all the glory, there are those that still have an affinity for the smaller 348ci engine. We can tell you that these heads are compatible with both. According to Smitty, “When using our 348/409 cylinder heads on a 348 block, there are a few concerns. One of these concerns is that they will not bolt directly onto a 1958 348 block. They can be used, but a small modification is required. There are a few water jacket hole passages that do not line up on the 1958 model year blocks. But, they do on 1959 and later model year 348 blocks. Also, the maximum lift at the valve on any year 348 is .550-inch, due to the valve clearance to the block in the cylinder chamber. There are no limiting factors that we are aware of when our heads are used on the ’61 through ‘65 409 blocks.”
Why It’s Better
We all know that cylinder head flow is crucial to create power, and a set of stock “high performance” 348 and “low performance” 409 cylinder heads use 2.06- and 1.72-inch valves, and flow roughly 210 cfm. The Edelbrock Performer RPM cylinder heads use 2.19- and 1.72-inch valves, and flow 282 cfm (at .600-inch lift). Also, the Edelbrock heads are cast from T356 aluminum, and weigh a parse 31-1/2 pounds each. That is nearly half that of an original Chevrolet iron head. In case you were wondering, the Edelbrock heads can be purchased in either bare or assembled versions.
The port wall thickness on the Edelbrock heads is substantial, allowing engine builders room to port and polish the runners to tune air flow. The factory head’s ports incorporate an angle as they enter the chamber area. Edelbrock incorporated a smoother approach that not only smooths airflow, but also increases that flow to the cylinders.
Upgrading The Upgrade
If you are building one of these legendary engines, don’t forget to upgrade with an Edelbrock Total Power Package. These dyno-matched components are available under one part number (2039). This all-in-one-box offers just about everything you need to top off your Chevy.
When the W engine was first designed (348ci), Chevrolet incorporated dual valve springs. Fast forward to today, and valve spring technology far surpasses that of 1958 technology, which allows Edelbrock to use modern, 1.55-inch diameter, single valve springs on their assembled versions. That spring rate is good for most applications using flat-tappet camshafts with lifts under .600-inch, while spinning the engine less than 6,500 rpm.
All of these added benefits makes the Edelbrock head a virtual no-brainer when it comes to understanding why you should upgrade, and Smitty agrees. “Anyone that chooses our Edelbrock 348/409 cylinder head, is getting a brand-new aluminum casting to use in place of a 50-plus year old cast-iron cylinder head. Most of the original cast-iron castings have been through a lot over the years, and they may need valve seats and guides, as well as general repair work depending on how they have survived over the decades,” he said.
Why Wouldn’t You
Smitty continued, “The biggest advantage is the delivered bolt-on performance that is better than original cast-iron versions. These heads will add value and horsepower to the build they end up on. We have built a 409ci engine with a single four-barrel carburetor using our entire Top End Kit, and have achieved 451 horsepower and 474 lb./ft. of torque using 91 octane pump gas. A factory, dual-quad equipped 409ci engine was only rated at 425 horsepower from the factory.”
If you’re building a 348ci or 409ci engine, finding a set of stock heads can be an undertaking in futility. The heads have been used and abused, and not built since 1965.
If the performance advantages offered by the Edelbrock head are not enough, let’s talk availability. There is a chance you might be able to locate a set of factory, cast-iron heads, but then you’ll likely need to rebuild them IF you do find a set. Figure in the cost of purchase, the machine work required, the likelihood of replacing valves, guides, and seats, you will probably have more money invested in a pair of low-performing cylinder heads than if you purchased the Edelbrock units. Unless you’re restoring an original dual-quad 409 car, why bother? In fact, just for fun, we went to a popular online auction site and tried to find a set of 348/409 heads, and we only found one pair. They came from a ’58 passenger car, and the asking price was $400 for the pair. They had no valves, springs, retainers, or locks—they were bare castings.
Now You Know
Finally, we asked Smitty if there is anything pertinent that he would like to let readers know about these heads, and he let us know, “The Edelbrock 348/409 cylinder heads have been around since November 2007. A lot of people thought we were crazy to offer them, and I’ll share with you that we sell out every production run we make. We have also developed more stuff for these Chevy W-series engines, like hydraulic-roller camshafts and lifters, timing chains and gear sets, and even mechanical fuel pumps. We also offer four different intake manifolds: small port 348/409 single- and dual-quad Performer RPM intake manifolds, and large port single- and dual-quad Performer RPM intake manifolds. We have also brought back vintage stuff like our Classic Aluminum Series Valve Covers.”
The intake runner volume of the Edelbrock cylinder head is 215cc, and the exhaust runner volume is 115cc.
Smitty finished by saying, “Shafiroff Racing has used our cylinder heads, a dual-quad intake manifold with two Edelbrock 600cfm carburetors, and made a whopping 620 horsepower on their 509/409 cubic-inch crate engine that they sell. If someone says the 409 is dead, they are severely mistaken.”
If you’re in the market to build a performance engine – be it W style, small-block, big-block, or LS, check out Edelbrock to get what you need.