The struggle between what works on the street, and on the track, isn't such a struggle anymore, thanks to creative engine builders and the right parts. Such is the case with the 632ci big-blocks built by Lizzard Racing and its owner Matt Grillo. Using a Merlin II block and Dart's famed Big Chief cylinder heads, the big- block of your dreams is only a checkbook away.
The Big Chief heads are built on the GM DRCE pattern that you'd find on a Pro Stock race car. That's not to say that they can't work in the sportsman drag racing world or even on the street. The fact is that they're one of the best flowing heads on the market, especially when matched to bigger cubic inches than which they were originally designed. Where a Pro Stock engine would have a ton of closer to 16:1 compression and only 500 inches, this engine features a 13.8:1 compression (race gas required) and 632ci, so the cylinder head's large intake runners are better matched for low-end torque. This particular engine was built for the street-legal drag racing wars, and since it has a stellar combo of crankshaft and rods, you can add power down the road with nitrous, a blower, a hotter valvetrain or more compression.
Last month we looked at how the short-block came together, now let's get an in-depth look at how Lizzard prepares the heads, manifold, carburetor, and pulls it on the dyno.
Taking you back to last month where we assembled the short-block, a Bullet A-Fire cam fires a four/seven swap for a smoother-running 1-8-7-3-6-5-4-2 firing order, and pushes .808-inch of lift on the intake, and .782-inch for the exhaust. This requires Manley NexTek valve springs set up for 280 pounds of spring pressure on the seat. Utilizing Manley titanium retainers matched with 10-degree locks isn't an option; it's a requirement. The Manley stainless valves are a good choice for this motor. Matt feels they work well for the engine's upper rev limit of 8,000 rpm, they save some money compared to titanium, and they accept more heat in a nitrous application down the road than ti valves would . These intakes measure 2.400 inches in diameter, and the exhausts are 1.900 inches. During handling, the castings are placed on cardboard sheets to prevent scratching, which preserves the sealing surfaces.
Grillo feels the Dart Big Chief is the finest head available to pull 1,100 hp out of a normally aspirated, single-four-barrel setup, right out of the box. Dart's "entry-level" CNC cylinder head ensures accurate and consistent results without requiring a lot of hand machining in the building process, thus providing considerable cost savings for Lizzard customers. This Big Chief came with a "Super Mod" 475cc port plus machined valve bowls, combustion chambers (86cc), and port entrances. The heads are then finished at the factory with hand-sized valve guides, and hand-blended bowls before assembly. | 
The valvetrain is measured and test-fitted before final assembly. Jesel's rocker-arm kit for the Big Chief uses three different stands and rockers: two for the intakes; one for the exhaust. Both the "dog-leg" and "Z" intake rocker-arm configurations use a 1.7:1 ratio, but have different offsets to reach around the large intake ports. A 1.75:1 ratio is used over on the exhaust side. Three different-length Manton pushrods are also used to attain optimum rocker-arm geometry. |
The .042-inch SCE copper head gaskets are painted with copper spray paint in this simple but effective spray box, which can be made from any cardboard box long enough to let a gasket hang. A pegboard hanger inserts through the rear. Gaskets hang freely, and can be left to dry without disturbing the painted surface. Matt likes the .042-inch gasket, as it is the most tried-and-true size for a motor of this kind (not to risk pushing a gasket under serious cylinder pressure) and other issues used in calculating this engine's base compression were manipulated through pin location, deck height, and chamber size. Remember that you can swap out these gaskets later to add or subtract compression, allowing for slight changes around more or less powerful combinations. | 
After a light bead of construction silver RTV is spread around the water jackets, the heads are lowered into place. Additional RTV is applied to the top corners of the heads at the lifter valley, to ensure a long-lasting seal for the crankcase. The heads are then torqued to 80 psi, the valvetrain is installed, and initial valve lash is set. |
Removing the masking tape from the water jackets reveals the last of the metal still inside the passages. The water holes in the heads were taped off to prevent metal chips produced during decking and valve seat machining from finding their way into the assembled motor during test fittings. Loose particles are trapped in the head, then taken away when the tape is removed at the last minute before the intake and valve covers are installed. | 
Some valve-cover studs on the top edge of both heads don't go through the valve-cover rail, assuring clearance between the valvetrain and the valve covers. Shortened studs are installed to keep the valve-cover gasket properly aligned, as well as creating the proper gasket-crush depth. |
Moroso's crank trigger (PN 6001) improves timing accuracy, is easy to adjust, and is virtually indestructible. The large-diameter trigger wheel eliminates deflection, and prevents "shadow firing" where the transducer can actually false-fire off the balancer. The magnets on the wheel are located so far away from the balancer that they virtually eliminate the possibility of misfires. During installation, the trigger depth is adjusted to the shutter wheel, and the initial timing is set using the index on the sensor mount. All advance and retard adjustments are then made on the sensor, not at the distributor. | 
SCE's intake gaskets (PN 18101) are glued to the heads using a permanent adhesive. Once dried, the gasket is trimmed to the ports. A thin film of never-seize is applied on the manifold side before the Dart cast aluminum manifold is lowered into place. The layer of never-seize on the gasket maintains sealing and eases removal of the manifold for inspection and maintenance. Matt uses silicone for end-rail sealing. Matt says the SCE gaskets have proven themselves to be excellent performers, using very durable gas and sealant-resistant materials, providing excellent sealing and long life. |
Lizzard uses Mallory's low-profile crank-trigger distributor (PN 6559054) on nearly every motor. The adjustable collar on its shaft accommodates both short and tall-deck blocks, and the overall compact size provides a great amount of clearance for any customer's setup and installation. The Mallory's small rotor and bolt-on cap prevent misfires under the most stressful operating conditions. | 
HVH's D-1 carb spacer is one-inch tall and is CNC-machined, helping it routinely deliver 15 to 20hp, according to Grillo. The D-1 is specifically made for the King Demon and other Dominator-style carburetors. Its machined contours convert fuel droplets off the throttle blades back into vapor, thus increasing the amount of burnable fuel in the combustion chambers. |
A King Demon RS series carburetor (PN 9838020DR) completes the installation. The King Demon features removable venture sleeves in order to make it work in any condition, or on different engines. Matt uses the 1195cfm sleeves for this application (this RS series carb allows for ratings from 1095 to 1495cfm, depending on the engine's requirements). Annular boosters pull more fuel, which will produce more torque at lower rpm by creating more signal, while also reducing area inventory inside the venturi. Overall, Matt says the Demon has the best fit-and-finish casting he's ever seen, as well as providing him nearly infinite tuning possibilities. As for that manifold, many think you need to use a custom sheetmetal version, but Dart has a cost-effective, bolt-on cast version available, and it's in use here. | 
In the dyno room, data from the initial pulls help zero in on the ideal carb tune, and cam and ignition settings. This motor produced 860 lb-ft of torque and 1,100 hp--impressive numbers from a single four-barrel without nitrous. |
Everybody has his or her own idea of just what "street driving" is. When Lizzard builds the street-driven version of its 632, Matt works very closely with his customer to identify exactly what this motor is expected to do. The basis is a 10.5:1 compression ratio, with a 1.1-1.2hp-per-cubic-inch formula, and the same high-end machining and quality materials used in Lizzard's competition engines. "Durability, reliability, and the feasibility of using pump gas are the absolute priorities," says Grillo. "Only then do the torque and horsepower numbers follow," based on the exact parts package agreed upon by Matt and the customer. This is the reverse psychology of building a racing engine--where high rpm horsepower numbers come first--and ensures that the sweet piece under that hood will actually get you where you want to go. Matt says that 50,000 miles can be expected, based on the amount of high-rev usage (over 6,000 rpm) the customer expects. Maintenance is a matter of regular valve-spring checks.
The biggest considerations separating the street-legal competition from the street-driven 632, lie in compression and valvetrain components. Pump gas, extended heat exposure, and varied rpm operating ranges, make preparing a monster motor intended to run at the track on the weekend, then cruise for 3,000 miles to that big summer event, a little more complicated than a motor you only hit for six seconds at a time. Matt typically uses a flat-top piston and a hydraulic-roller cam, which provide a very durable, streetable combination, which talks back to you with an average of 800 lb-ft of torque, and 650 hp. Other differences include a "driveability" tune on the King Demon, steel connecting rods, and, in most cases, a smaller cylinder head and manifold combination, as most customers don't have the room for a Big Chief setup under their hood. Matt's favorite alternate for the full-race head-intake combination is the Dart 360 head with Edelbrock's Super Victor manifold. This will often allow the motor to tuck in comfortably, and invite an air cleaner, power steering, and A/C to come in and party-down too. On top of all this is a bevy of options, including vacuum pumps and aluminum blocks. Oh, and let's not forget about the spray.