412 inch Small Block Build - The Z06 Slayer

In our March and April 2007 issues we ran a series called "The BionicCamaro." The background behind the Bionic Camaro is this: A stock-styledand stock-built '69 Camaro is undergoing a plethora of wicked upgradesthat will make it a serious street contender and bracket brawler. Youcan't be a contender unless you have the power to punch, and that punchcomes from the mill hiding under the hood. As you can well guess, thestock small-block was ditched in favor of a more appropriate powerplant.

Todd Heimroll, owner of the Camaro, stated his goal was to beat a ZO6Corvette and that's it. Some people set goals to lose weight or tofinally clean the garage this year ... but beating a ZO6? Now that's ourkind of target. In the first two installments we covered the front andrear revamps of the suspension. But all the grip in the world won't helpyou without horsepower under the hood.

Let's get started with a solid foundation for this build. Forget about salvaging a junkyard block and all the machining involved in bringing it back to life. A Dart "Little M" small-block was a solid choice. The Little M block is of an iron alloy casting and comes with billet steel 4-bolt main caps and a 4.125 cylinder bore with extra thick cylinder walls. Lirones Motorsports gave it a touch more. Each cylinder measures in at a 4.155 bore. With a stroke of 3.800-inches, it brings the total displacement of this Mouse up to 412 cubic inches.

To achieve his goal of out-gunning the ultimate Corvette, Todd turned toLirones Motorsports for the buildup of his engine. Todd's vision ofpulling away from a plastic surgeon and his Z06 Corvette with a humblelooking '69 Camaro is the stuff dreams are made of. This Camaro is nosleeper--it's built to be a slayer.

Let's get started with a solid foundation for this build. Forget aboutsalvaging a junkyard block and all the machining involved in bringing itback to life. A Dart "Little M" small-block was a solid choice. TheLittle M block is of an iron alloy casting and comes with billet steel4-bolt main caps and a 4.125 cylinder bore with extra thick cylinderwalls. Lirones Motorsports gave it a touch more. Each cylinder measuresin at a 4.155 bore. With a stroke of 3.800-inches, it brings the totaldisplacement of this Mouse up to 412 cubic inches.

Without a doubt, the key to making any kind of decent power lies in theselection of the cylinder heads and the valvetrain. No doubt, AFR hasestablished a reputation of creating some high flowing aluminum cylinderheads. The AFR 227 heads used in this build are the Competition versionand are fully assembled. They feature 100 percent CNC-ported 227ccintake runners and 100 percent CNC-ported 76cc combustion chambers. Theexhaust ports on the 227s are 80cc, while the valves measure 2.100-inch(intake) and 1.600 (exhaust) with 1.550 roller springs. The cam that wasused in this build is a custom-ground solid roller from Sig Erson. Thelift on the intake and exhaust both measure at .580. The duration on theintake is 256 @ .050, while the exhaust is 263 @ .050 with a 108-degreelobe separation. Lunati roller lifters, a Crane adjustable timing chain,Manley push rods and Harland Sharp rockers finish the rest of thevalvetrain. Keeping the entire system in time is an MSD distributor andbox.

Without a doubt, the key to making any kind of decent power lies in the selection of the cylinder heads and the valvetrain. No doubt, AFR has established a reputation of creating some high flowing aluminum cylinder heads. The AFR 227 heads used in this build are the Competition version and are fully assembled. They feature 100 percent CNC-ported 227cc intake runners and 100 percent CNC-ported 76cc combustion chambers. The exhaust ports on the 227s are 80cc, while the valves measure 2.100-inch (intake) and 1.600 (exhaust) with 1.550 roller springs. The cam that was used in this build is a custom-ground solid roller from Sig Erson. The lift on the intake and exhaust both measure at .580. The duration on the intake is 256 @ .050, while the exhaust is 263 @ .050 with a 108-degree lobe separation. Lunati roller lifters, a Crane adjustable timing chain, Manley push rods and Harland Sharp rockers finish the rest of the valvetrain. Keeping the entire system in time is an MSD distributor and box.

It seems lately we've seen many vehicle owners paint their engine blocksto match their vehicle. Why would this one be any different? Afterprepping the block for paint, Lirones Motorsports shot it in the samecolor as the vehicle. If you're curious on the procedures of blockpainting, we'll have a tech article on that process in a future issue.	An Edelbrock 2970 single-plane aluminum intake was selected for thisbuild, and this one has been port matched with the heads for preciseflow of the fuel/air mixture.	Topping the intake is a Holley HP series830-cfm carburetor.
Next came the Callies crank with a 3.800-inch stroke, Clevite "H" seriesbearings, Manley H-beam steel rods measuring 5.850-inches and a set ofJE flat top pistons. The compression measures in at a very streetable10.4:1, which will be fine for this pump gas-only engine.	After the engine had been completely assembled, it was time for pulleyselection. And not just any kind of pulley system, either. A BilletSpecialties small-block Tru Trac system was chosen to give the enginelooks and performance. The serpentine system also includesair-conditioning and power-steering pulleys as well.	Finally, the dyno day had arrived and the engine made its way toVrbancic Brothers Racing in Ontario, California. After the engine washooked up to the dyno, Bob and George Vrbancic decided to check theengine before actually starting it and making a pull.
One thing was thatthere was clearance issues with the rocker arms. The rocker arms weretouching the retaining clip on the springs. The dyno pull was called offthat day while the rocker arms were machined in order to clear thesprings.	Judgment day arrived not long after. The 412 was set to go. Afterseveral minutes of breaking the engine in and checking the vitalnumbers, it was time for a pull.	After a few pulls on the dyno, the Slayer came up with some prettyZO6-like numbers.
Maximum torque was 537.2 lb-ft at 4700 rpm and peakhorsepower came in at a robust 555.3 at 6200 rpm.	For the full effect, click here to watch a video clip from the dyno test of our 412 small block: WMP / QT