Some time ago, we told you about Holley’s giveaway sweepstakes involving a 427 cubic-inch LS engine, fitted with a pair of TorqStorm centrifugal superchargers, being built by Prestige Motorsports. Recently, they put the engine on the dyno to get a “low-boost” pump-gas tune installed into the Holley Terminator-X ECU, as well as a higher-boost race-gas tune.
In the previous article, we went over some of the parts used, as well as the part numbers, but in the video, Jeff Huneycutt details the engine build in much more detail (it’s well worth the watch). A quick recap of some key specs on the engine is that it displaces 427 cubes via a 4.125-inch bore and 4.00-inch stroke in the Dart LS Next block with a relatively low 9.6:1 compression ratio.
It features a set of Prestige Motorsports 11-degree cathedral-port heads, with six bolts per cylinder, 255cc intake ports, and 2.02-inch intake and 1.60-inch exhaust valves. The camshaft is a custom-ground hydraulic-roller from COMP Cams, with 238 degrees of duration at .050-inch on the intake side, and 248 degrees on the exhaust side. It has .604 inch of lift at the intake valve and .597 at the exhaust valve.
The twin TorqStorm centrifugal superchargers feed boost through the Holley Lo-Ram LS intake and the cylinders are fed fuel from a set of FIC 1,000cc/min fuel injectors. Spark comes from a set of MSD ignition coils. As mentioned earlier, all of those aspects are controlled via a Terminator-X ECU.
The first dyno pull was performed naturally aspirated, just to get a baseline. Keeping in mind the 9.6:1 compression ratio, the engine made a respectable 512.2 horsepower at 6,000 rpm and 491.1 lb-ft at 4,900 rpm. With that complete, the team installed the two superchargers and plumbed the setup through an air-to-water intercooler.
The initial setup is using TorqStorm’s 3.25-inch supercharger pullies which create right at 15 pounds of boost at 6,700 rpm. With the pump-gas tuning complete the number showed a significant increase over the N/A runs, posting 1,057.3 horsepower at 6,600 rpm and 864.5 lb-ft of torque at 6,000 rpm.
Not content with the 1,057 horsepower number, the team at Prestige swapped on a 3.100-inch pulley, filled the fuel cell with race gas for some added safety, and made another hit. The new power numbers were commensurate with making 18.2 psi of boost at 6,800 rpm. 1,133.4 horsepower at 6,500 rpm and 944.5 lb-ft of torque at 6,100 rpm was the final tally for this engine.
While this LS produced solid numbers from an engine designed to live on the street, Prestige will be delivering it to the winner in bit milder configuration, making an estimated 750 horsepower. Not a bad deal for whoever ends up with this 427-cube monster between their frame rails.