509 Aluminum Big Block Engine Build - W=Wow!

Lamar Walden Put Together The First Of His All-Aluminum W-Motors And We Were There.

Brad Ocock Oct 1, 2010 0 Comment(s)

Like a lot of other segments in our hobby, the legendary 409 is enjoying a new heyday. The beginning was about 10 to 15 years ago when stroker kits hit the scene, punching displacement up to 482 ci. Within the last four or five years, strides have been made with aluminum heads, dedicated distributors, reproduction and aftermarket oil pans, roller cams and roller rockers. Leading the charge since running a blown and injected 409-powered '33 Willys in the early '60s has been Lamar Walden.

Sucp_1010_26 409_aluminum_big_block_engine_build Prototype 2/27

From billet blocks to rocker arms, Walden has made just about everything possible for a 409. His most recent venture has been to team up with Bill Mitchell at World Products to develop an aluminum 409 block.

"The problem is that blocks have just about dried up," Walden says. "You can get race or street heads and intakes, billet timing chains, valve covers, crank kits, good pistons, and everything else. The only thing you can't get-and the most important-is the block."

There were originally two factory blocks: passenger car and truck. The truck blocks are the most common, but have a handicap in the form of a large, compression-killing notch cut in the side of the bore. Opinions vary on "The Notch." Over the years, it's been said the notch unshrouds the exhaust valve, which is true. However, the benefit of the unshrouded valve usually doesn't outweigh the compression drop. It's good for a forced induction application, and some race engines. Prices for buildable passenger car blocks range from $2,500-$4,000 (and cracked cylinder walls or water jackets aren't deal breakers), while truck blocks aren't far behind.

As much as we love the '09, we have to be honest and admit there are several shortcomings: The deck is a little on the thin side, making high/race compression ratios, forced induction or nitrous a dicey proposition (flex does bad things to head gaskets). They also have a tendency to pull head bolts out. The area where the exterior of the block meets the deck is also thin-Walden has dozens of blocks that were cracked from running too hot or freezing. (Fortunately, he's developed a method of repair).

And then there are the 409-specific bits that can add hundreds of dollars to a build: oil pan, timing cover, distributor (or spacer sleeve) and harmonic balancer. Reproduction oil pans are in the neighborhood of $300, while original timing chain covers are scarce. And you need the right one, because there are two timing tab locations.




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