Building solid packages that perform as advertised is one of the hallmarks of the team at Prestige Motorsports. Their standard 582ci big-block Chevrolet engine is guaranteed to produce 700 horsepower and 700 lb-ft torque, but this particular customer was looking for more.
“What makes this combination unique is that the customer wanted twin carbs. Initially we set out to use an as-cast tunnel ram intake, but once the overall height of the engine was established we no longer had that opportunity. At this point we now had to fabricate a manifold,” says Prestige’s Doug Aitken.
A traditional sheetmetal intake is designed for all-out top-end performance, but in this instance the intake manifold was selected purely for the appearance aspect, and in fact, caused the fabrication process to be a bit more difficult.
“With the height we were given the intake had to be much shorter than we would naturally build it. Keep in mind the customer’s expectation was to have the look of dual quads and still be driver friendly, but he didn’t really have a peak power requirement,” Aitken explains.
The engine uses one of Dart‘s Big M engine blocks that’s been filled with a 4.375-inch stroke Eagle forged crankshaft that swings 6.535-inch Eagle H-beam connecting rods secured with 7/16-inch ARP 2000 capscrews. The 4.600-inch cylinder bores are filled with JE pistons to finalize the overall displacement at 582 cubic inches. The pistons have been lateral gas-ported to assist the ring seal under demanding conditions.
Dart was also tapped for a set of their Pro 1 345cc as-cast cylinder heads, with valves driven by a Comp Cams solid-roller camshaft. This particular engine used .680-inch lift across the board, with 251/260 degrees of duration at .050-inch lift, and was ground on a 108-degree lobe separation angle.
Aitken also selected a set of Scorpion mechanical roller lifters, Scorpion’s Endurance Series roller rockers, and Dart’s stud girdles to keep the valvetrain under control.
The engine also uses a modified Moroso oil pan, MSD Pro Billet slip-collar distributor, and a set of custom-fit wires. Prestige also selected a set of custom blue metering blocks for the carburetors to match the vehicle’s color scheme.
After the manifold was fabricated, polished, and clear-coated, a pair of Quick Fuel RQ750 carburetors was slapped on top, and the engine was mounted to the dyno.
“After break-in, valvetrain lash and inspection we were very surprised at the low end torque this beast made the first time we loaded it down. Equally, we were just as surprised what the peak power was on the first full sweep test. This engine is designed around our single-carb 582 700 hp combination using a Dart 4150 single plane intake and Quick Fuel RQ 1050 carburetor. With the custom manifold and dual quads we were making over 120 hp more than the package engine!” says Aitken.
He also noted the ability to turn the engine higher in the RPM range than their standard 582ci BBC combination, mainly because the dual-quad manifold did not present any sort of restriction to the intake tract, where that is the limitation on the packaged engine.
The Prestige team is very happy with the engine’s responsiveness.
“The throttle test we perform showed extremely quick throttle response and acceleration. This test consists of loading the engine at 2000 rpm, such as cruising mode. We apply approximately 150 lb-ft of torque steadily, than nail the throttle. This simulates what the engine will be like in the vehicle and how well it takes throttle. We feel this is a very important step for any street engine developer to perform,” Aitken explains.
With the small camshaft and pump fuel required for the build to present easy street manners, achieving 800-plus horsepower is no easy feat. Aitken says even more would be possible from this basic combination with some upgrades to the induction system and camshaft profile.