Walden and World Products addressed these issues with a new aluminum block, that actually measures 509 with the as-delivered 4.5-inch bore and a 4-inch stroke crank. There's a thicker deck, a dual-pattern oil pan rail to accept an original 409 pan or a readily-available big-block Chevy pan, and a BBC timing chain cover pattern to accept any factory or aftermarket piece, including billet covers and belt drives.
"We kept the things that make it a 409," Walden said. "Obviously, the heads and the deck are what make the engine, but nothing looks like a 409 pan so they can still use it, and we had to keep the 409 water pump, too. That's almost as visually important as the heads."
What has many excited is the price for the 509 block-at press time, the block was shown on World's website retailing for $5,549, which sounds like a chunk-until you do the math. Take a good-deal $2,500 iron block, then add all the machine work required to make it usable. Boring a 409 not only requires specific know-how, it requires several additional machining operations due to the combustion chamber being in the block. Many blocks require a sleeve or two by now, which is no big deal, but it's added expense. And then of course you still have 2-bolt main caps, unless you step up to 4-bolt caps and the expense to install them-required with a stroker crank. And the main stud kit. Toss in the OE oil pan and timing cover, and you'll easily have $4,000-$6,000 in a prepped block ready to go. You could have a better, stronger and lighter W-block (with more cubes) for the same money.
Lamar had the first two prototype World 409 blocks shipped to his Doraville, Georgia, shop, and we followed along while he put the first together for a customer. The build was simple: mild cam (with specs Lamar guards like he's still Pro Stock racing), mild 10.5:1 compression ratio, Lamar's "-690" aluminum street heads topped with a brand-new Hilborn injection intake converted to EFI. The bruiser thumped out 667 lb-ft of torque at 5,500 rpm, and was still climbing at 655 hp when they ended the pull at 6,500 rpm. "It's not a race motor," Lamar told us, "so there was no point in running it all the way up."
With a set of his Z11 race heads, more compression and cam, another engine they built for Nostalgia Super Stock racer Barry Camp went well past 750 hp and another 2,000 rpm. And that was through a pair of carbs. The Hilborn they tested on this engine had 2.5-inch throttle blades, but 3-inch discs are available. The blocks can also be punched out a lot more, so we're certain Walden hasn't come close to wringing all there is from the new aluminum W-motor.