Power to Burn
If you're serious about making lots of power, the GM Performance Parts ZZ572/720R will fill the bill. This engine is based on the Gen VI tall-deck big-block and is stocked with hard-core parts like rectangular port aluminum heads, a mechanical roller camshaft with 0.714-inch lift, and a 1,090-cfm King Demon carburetor that helps to deliver 720 horses at 6,250 rpm and 685 lb-ft of torque at 4,500 rpm. Plan on adding a big set of headers and exhaust. With this much torque you'll want to keep the rearend gear ratio in the neighborhood of 3.55:1, but you should at least have a 12-bolt housing or, better yet, a Currie 9+ or Strange S-60. The camshaft (266/274 degrees of duration at 0.050-inch lift) will require a high-stall converter mated to a very strong automatic. Camaros require frame connectors, and all cars will need a well-engineered suspension and brake system. To keep the engine temp in check, plan on upgrading the cooling system with an aluminum aftermarket radiator and electric fans. But when you're done you'll be the wow of the town.
| Type: | GMPP ZZ572/720R (PN 12498826) |
| Block: | GM tall deck |
| Crankshaft: | Forged 4340 steel |
| Connecting Rods: | Forged 4340 steel |
| Pistons: | Forged aluminum |
| Cylinder Heads: | Rectangular port aluminum |
| Valve Size: | 2.25-I/1.88-E |
| Rocker Arms: | Roller 1.7:1 ratio |
| Retainers: | Hardened chromemoly |
| Camshaft: | Mechanical roller 0.714-inch lift, 266/274-degrees duration at 0.050-inch lift |
| Compression Ratio: | 12.0:1 |
| Induction: | 1,090-cfm King Demon carburetor mounted on a tall deck single-plane intake manifold |
| Oil Pan: | Six quart with windage tray |
| Water Pump: | Aluminum |
| Distributor: | Multiple spark discharge |
| Horsepower: | 720 at 6,250 rpm |
| Torque: | 685 lb-ft at 4,500 rpm |
| Max Recommended Speed: | 6,750 rpm |
SourcesGM PERFORMANCE PARTSDept. CHP
(800) 577-6888 (nearest dealer)
www.gmgoodwrench.com
Speed-O-Motive 750hp Nitrous Small-Block
Aluminum is great, but there's still a lot to be said for cold, hard steel and its unparalleled strength. That's the idea behind this Jekyll-and-Hyde small-block creation from Speed-O-Motive. A stout Dart small-block filled with an all-forged-steel rotating assembly provides the basis for a motor that can handle just about anything. According to Speed-O-Motive's George Ullrich, another crucial component in this high compression creation is the SCE I.C.S. Titan head gaskets, which have an internal combustion seal--virtually eliminating leakage whether using steel or the optional aluminum heads (even while enduring 300-horse shots of juice).On the other hand, this 355ci mill is intended to be a creditable street contender when running naturally aspirated. To that end, Ullrich and Speed-O-Motive cooked up a custom cam grind. It's aggressive, Ullrich admits, with lots of lift and duration to pump out loads of mid- and top-end power. In fact, exhaust duration is a bit longer than the intake to help vacate burnt gasses while under squeeze. This is a heavy-breathing motor, to be sure. On the other hand, the LSA has been opened up to 112 degrees to help flatten out the power curve and pump-up low-end power (108-110 degrees would be normal for a high-rpm nitrous motor). In this case, compromise is a good thing. That little bit of bumpstick finagling makes for a strong street motor that can go psycho at the push of a button--and live to do it again.
| Type: | Dart Little M small-block |
| Block: | Cast-iron, 4.030-inch bore, splayed ductile iron four-bolt main bearing caps |
| Oiling: | Milodon deep-sump pan with screen-style windage tray, high-volume oil pump |
| Crankshaft: | Speed-O-Motive 4340 forged steel, 3.48-inch stroke |
| Connecting Rods: | Speed-O-Motive 6-inch forged-steel H-beam |
| Pistons: | JE forged with Total Seal TSI rings |
| Cylinder Heads: | Dart Iron Eagle, 230-cfm runners, 64cc combustion chambers, 2.08-inch intake valves, 1.60-inch exhaust valves, screw-in studs and hardened guide plates, SCE I.C.S. Titan head gasket (same-spec Dart Pro-1 aluminum heads an extra-cost option) |
| Camshaft: | Speed-O-Motive spec'd Comp Cams solid-roller, 248/254 degrees duration at 0.050, 0.576/0.582-inch lift, 112-degree LSA |
| Compression: | 10.3:1 |
| Valvetrain: | 1.52:1 Comp Cams Pro-Magnum roller rockers, Manley 4130 heat-treated pushrods, Dart rocker stud girdle |
| Induction: | Dart single-plain intake manifold, Speed Demon 850 carb |
| Ignition: | MSD Digital 6 with nitrous retard and MSD billet distributor |
| Power Adder: | Zex 4 BBL Perimeter Plate nitrous system, 100-300hp shot |
| Exhaust: | you pick it |
| Output (estimated): | 450 horsepower/425 lb-ft of torque sans juice, 750 horsepower/730 lb-ft of torque on the squeeze |
SourcesSpeed-O-Motive131 N. Lang Ave., Dept. CHP
West Covina, CA 91790
(626) 869-0270
www.speedomotive.com
The Mission: Vortec-head TBI 305
We could also call this the "Use What You Got" special, but either way, we were pleasantly surprised when we turned a run-of-the-mill, 170-horse throttle body 305 into a tire-destroying 330-horse (estimated at the crank) mighty mouse. Using the same 22-percent drivetrain loss factor, which engine builder Superior Automotive recommended since our Mission 305 motor was running through a near-dead 700-R4, we also came up with 388 lb-ft of torque. And while we wouldn't call this conversion easy to accomplish, the recipe is actually pretty basic.Superior took a set of Vortec heads, already well-known for their excellent breathing capabilities, and made them hyperventilate; the final figures of 252-cfm intake flow and 181 cfm on the exhaust at 0.050 valve lift far surpassed the untouched Vortec castings, much less the stock L03 heads. Compression, of course, was raised above the stocker's 9.3:1 ratio. A cam more aggressive than the stock broomstick was created to take advantage of all this airflow. Turbo City's 620-cfm Super Flow throttle body, along with a custom chip, kept the jugs full, a potent Crane ignition system fired off the mixture, and the waste products were quickly evacuated courtesy of Edelbrock exhaust components. You can read all about it in our Jun. and Sept. '04 issues, but the bottom line is that we created a kick-ass 305 that remains eminently streetable-and all this without removing the 30,000-mile short-block.
| Type: | Chevrolet L03 TBI 305 |
| Block: | GM cast-iron, two-bolt main bearing caps |
| Oiling: | stock |
| Crankshaft: | stock |
| Connecting Rods: | stock |
| Pistons: | stock |
| Cylinder Heads: | Ported GM L31 Vortec heads with spring upgrade for hydraulic roller cam and up to 0.570-inch lift, machined for 53cc combustion chambers |
| Camshaft: | Crane Cams 0.510/0.520-inch lift, 210/214 duration at 0.050, 114 LSA |
| Compression: | 9.8:1 |
| Valvetrain: | Crane Gold Race 1.6:1 roller rockers, Scoggin-Dickey spring upgrade |
| Induction: | GMPP Vortec TBI manifold, Turbo City 620-cfm throttle body with blueprinted injectors |
| Ignition: | Crane Fireball HI-6 CD ignition with LX92 Fireball coil, Moroso Blue Max plug wires |
| Other: | Computer chip tuning by Turbo City, Anaheim, CA |
| Exhaust: | Edelbrock TES headers, Magnaflow high-flow cat, Edelbrock cat-back |
| Output: | 257.06 hp at 5,150 rpm, 294.96 lb-ft at 3,500 rpm |
SourcesSuperior Automotive Engineering675 W. Woodland Dr., Dept. CHP
Anaheim, CA 92801
(714) 503-1880
www.superiorautomotive.com