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Merlin-X 409 Engine Prototype - Legend In Aluminum

A Look At World Product's Merlin-X 409 Prototype Aluminum 409 Engine Block.

By Brad Ocock, Photography by Brad Ocock

We can't really put our finger on just what it is that makes the 409 such an iconic engine with such a huge following. There's more to it than just the song. (And frankly, if we never hear the song again, we'll be fine with that.) There's also more than just being the first big-block Chevy, or those distinctive scalloped valve covers. Unlike the Ford FE and Max Wedge Mopars, the 348-409 W-engine had a relatively short life span. Mopars used the same basic design well into the '70s on the 440, and the FE also enjoyed a long run.

While the 409's star didn't burn too long, it certainly did burn brightly. The 409 was the first high-performance big-block out of the gate, and the others played catch-up. That short couple of years built and cemented the 409's legend. Okay, the stupid song probably helped too.

But there was more to it than that. The 348 with 3x2s came out in 1958 and held its own thru 1960 while all the big cars were being fitted with bigger and more powerful engines; Chryslers had the 392 Hemi but then dropped in power with the 383 and 413, Buicks were never really in the game with their 364-inch and later 401 Nailhead, but Ford busted out the 352 FE and the Mercury/Edsel/Lincoln 430, while Olds had the 371 and 394 Rockets. The Chrysler 354 and 392 Hemi was dominating on drag strips and NASCAR ovals, but that fell off considerably when Chevy turned up the wick with the release of the 409 at the tail end of 1961. The engine was so new, only 143 cars came with them, and there was some question in the minds of NHRA whether or not the 2x4 induction was factory-installed or a dealer option, as they initially classified them as A/FX.

Forty-odd years later, the 409 is enjoying a renaissance. We now have a few sources for aluminum heads, stroker rotating assemblies have pushed the displacement to 480 inches and beyond, new aluminum water pumps are available, and MSD makes a new distributor for them. The only thing lacking for a complete aftermarket 409 engine is a block-and it's severely lacking. Factory 409 blocks come in two flavors: passenger car and a lower-compression truck block. Both are expensive, but fewer passenger car blocks rolled out of the factory than truck 409s, so the car blocks command a premium. And unlike most other overhead valve engines, the drop in compression with the truck engines is caused with the block itself, rather than the head-a large relief was cut into the edge of the bore.

Because the truck blocks are more common and cheaper, builders have come to decide that the truck blocks are more desirable for performance builds because that notch unshrouds the exhaust valve, improving flow. We've asked 409 expert Lamar Walden about this in the past, and his answer is simple: unless it's a supercharged application, compression beats an unshrouded exhaust valve.

If you've never seen a 409 block or head up close, it's obvious why the design was left in the past. It was basically Chevrolet's answer to the flat head, writ large. The underside of the head is flat, with no combustion chamber-just valves on a smooth plane. Rather than the engine block's deck being 90 degrees to the top of the pistons, the deck is angled at 74 degrees to the stroke. The inboard side of the pistons' dome is machined at a matching 74-degree angle to kiss the bottom of the head, while the outboard side of the piston dome remains at 90 degrees. This creates a triangular wedge between about 3/8 of the piston's dome and the bottom of the head. This area is the engine's combustion chamber.

Piston design, ring placement and valve relief will all affect compression ratio, as will head gasket thickness. These are all variable, but that truck block's big notch in the edge of the bore adds space to the combustion chamber that can't be offset, and you lose at least a full point of compression over a passenger car block.

As we said, the only thing missing from the aftermarket line-up for the 409 is the engine block, the price of which has been steadily climbing in recent years. Today, a $1,000 passenger car block evaporates like a water drop on a hot skillet, $2,500 for a bare block is considered a bargain, and prices of $3,500 to $4,000 are pretty common. This is based not only on talking with Lamar and other people who have been buying 409 blocks, but also from our personal observations while watching Craigslist, eBay, and swap meets. Truck engines are a lot cheaper, but they're still painful on the wallet. While 348 passenger car and truck blocks are much more common than either of the 409s, with bare blocks trading in the hundreds of dollars rather than thousands, the cylinder walls of the 348 block's 4.125-inch bore can't be taken out to the 409's 4.3120-inch hole.

It's also worth pointing out that those prices are for easily serviceable blocks. By now, if the blocks haven't been worn out to the point of needing a 0.060-inch overbore, they've often sat so long the cylinders need that much to clean up the rust pits. Provided none of the cylinders are cracked ... sleeving several bores is pretty common by now.

We're not going to try and make it sound like the 409 blocks are junk or anything like that, because they're not, but like all engines they have a few shortcomings as designed by the factory. The Achilles Heel of the 409 blocks is they are prone to cracking where the deck meets the block's side. It can be repaired, but it's an added expense, so you need to recoup that money on the front end when you buy it. They also only come with two-bolt mains, which is fine for a stocker, but if you're going to slip a 454-inch crank into one, you'll need to step up to a set of four-bolt main caps as well.

This is not only to strengthen the bottom of the block and hold the crank more securely, but it maintains your stroker crank's integrity. To turn a standard big block Chevy crank's main journals down to fit in a 409 (a 454 crank is the most common used for a stroker 409), you'd need to knock 0.250-inch off. If the machine shop told us our crank needed to be turned 0.050-inch to clean up the journals, we'd tell him to throw the crank on the scrap pile. To put one cut five times that amount in an expensive block makes no sense. And cutting 0.125-inch out of the stock two-bolt main caps is no good either.

Though not a problem with the block directly, you're limited to 348/409 timing chain covers and oil pans, which usually haven't escaped 40 years without incident. Original oil pans are usually pretty expensive, and reproductions have been available for a couple years now, but either will still set you back a few hundred dollars. Though equal in length to a regular big-block Chevy, the pan rail's bolt pattern is different. The timing chain covers are also unique to the 409; again, same shape and mounting pattern as a big-block Chevy, but the crank snout on a 409 crank is identical to the snout on a small-block Chevy, so the timing chain cover is stamped like a big-block Chevy, but has a seal race for a small-block.

You've seen the pics through this story, so you know there are big things on the way for the 409. Nostalgia is bigger than ever, and a lot of speed parts are becoming available for several different vintage engines. With modern product fully covered, big manufacturers are starting to set their sights on the smaller markets, and nostalgia motors are a previously un-serviced niche. The big benefit to consumers is that the major players already have the tools to produce complex and expensive components such as cranks, heads, pistons, and in some cases, engine blocks, so they've got the infrastructure to produce niche components.

World Products has teamed up with Lamar Walden to develop a brand new aluminum 409 block-big news for anyone wanting to put one of these legendary engines on the street or race track, and great news for the restorers, as they won't have to compete with racers and rodders for blocks.

Lamar started with a new World BBC aluminum engine block, and began converting it over to 409 specifications, beginning with milling the 90-degree deck and fabricating a wedge to correct the deck angle so the heads would bolt up. At the front of the engine, Lamar closed off the standard BBC water pump ports and located a set of mounting bosses for the 409 water pump. Rather than reinvent the wheel, the standard BBC timing chain cover and oil pan rail were retained, which is a nice bonus for customers.

With the deck angle, combustion chamber and water pump bosses adapted to the block, Lamar sent it back to World, where patterns and molds will be pulled off of it to start casting with brand new aluminum 409 blocks.

Enhanced blocks are one of the benefits found on World's BBC aluminum castings. Lamar once built a twin-turbo 409, and found that with enough boost, the block will split through the lifter valley like a piece of firewood, only holding together with the bellhousing and timing cover. World blocks feature thick reinforcements between both banks through the lifter valley, not only keeping the block together, but limiting bore deflection under load as well. The World BBCs also benefit from a relocated, raised main oil galley, allowing billet four-bolt splayed bolt main caps, which ship with the blocks, along with premium fasteners-the mains will be the larger BBC diameter, so material doesn't have to be removed from the webbing as when a factory 409 block is align bored to BBC crank specs.

The cam journals are also the standard BBC specs, while stock 409s share cam journal diameter with the small block Chevy, and the journals are raised to in the block to clear big stroke cranks. The World 409 blocks will also have a thicker deck, eliminating the tendency for the block to crack there. Walden tells us the blocks will come standard with a 4.500-inch bore, and can be take out to 4.600-inch. "With a 4-inch stroke crank, and long 6.135-inch rods, it'll be 509 ci," Lamar told us.

His LWA aluminum -690 heads flow enough to support over 500 cubic inches, so running one on the street isn't a problem. Max out the bore and adding a long stroke 4.75-inch crank pushes the displacement to a tick over 630 cubic inches, and you will need a set of Walden's Z11 aluminum race heads. Is there a Nostalgia Outlaw class?

Final pricing won't be determined until the first run of blocks come back from World's foundry, but they should be in the same neighborhood as World's Merlin big-block Chevy castings, and not much more than you'd pay for a good passenger car block fully prepped and ready for a 4-inch crank. That's a pretty good neighborhood, and one we can't wait to buy into.

SOURCES
Lamar Walden Automotive
7-70/-449-0315
www.lamarwaldenautomotive.com
World Products
Ronkonkoma
NY
6-31/-981-1918
www.worldcastings.com
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By Brad Ocock
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