When it comes to the peak of Ford Performance, the GT40 (in all of its variants) is almost inarguably “it.” So, any powerplant being built to motivate the pinnacle vehicle, must be an equally impressive piece of engineering. When a customer approached Prestige Motorsports for such an engine for his GT40 replica, the team knew exactly what was expected of them — an all-aluminum 427.

Luckily for us, Jeff Huneycutt of The Horsepower Monster was around when the engine came together, and was able to capture all of the Blue Oval awesomeness being assembled. Starting with a Carrol Shelby aluminum 9.5-inch deck Windsor block that tips the scales at a mere 95 pounds. It comes with meaty sleeves that will handle the intended 4.125-inch bore without blinking.

Into the billet four-bolt mains went a 4.0-inch-stroke forged Eagle crankshaft. Attached to the Chevy 2.100-inch rod journals are a set of Eagle forged 4340 H-beam rods, measuring 6.250 inches, center-to-center. Hanging off of the rods is a set of Prestige Motorsports-spec forged DSS pistons with a 1.2mm, 1.2mm, 3.0mm ring pack, an 8cc dish, and a slipper skirt design. Both the rod and main bearings are King Engine Bearings pMax Kote bearings. A Melling M83 oil pump provides lifeblood to the mill, which sits inside a fabricated-steel low-profile Aviaid oil pan with a seven-quart capacity. An Innovators West harmonic damper finishes off the short block.

Topping off the 427-cube aluminum short-block is a set of Prestige Motorsports’ heads. Starting life as an aluminum Brodix Track 1 casting, all of the final specs are machined by Prestige. They feature a high-flowing 220cc intake runner and 72cc combustion chambers for a 10.5:1 compression ratio. Filling those chambers are a 2.100-inch-diameter stainless steel intake valve, and a 1.570-inch exhaust valve. A set of .041-inch Fel-Pro composite head gaskets work with a custom set of extra-long 1/2-inch ARP head studs to seal everything up.

The aluminum 427 short-block makes for a lightweight base upon which to build. Besides making power, the engine needs to be svelte to keep the balance and handling dynamics of the GT40 replica true to the real deal.

The camshaft is a big Prestige-spec hydraulic-roller bumpstick measuring .683 inch of gross lift on the intake and .656 inch on the exhaust. Duration specs are a hefty 259 degrees at .050 inch of lift on the intake and 269 degrees on the exhaust, with an undisclosed lobe separation angle. A set of Gaterman hydraulic-roller link-bar lifters ride on the big ol’ cam lobes and move the 7.450-inch, .080-inch-wall chromoly pushrods.

Those actuate a set of Jesel 1.6:1 aluminum shaft rocker arms, which are both stiff and lightweight. Keeping the valves under control is a set of dual valve springs, with just enough pressure to handle the significant lift and engine speeds of the engine, while not prematurely wearing parts. They are held in place by stainless steel locks and retainers.

Feeding the aluminum 427 is a Borla stack injection system. Besides the individual throttle bodies, the injection system offers all the modern amenities you expect from a modern EFI system. The Borla injection is deceptively old-school. Behind the classic looks is an incredible amount of high-end technology. A Holley Dual-Sync distributor sits up front, and the engine is controlled by a Holley EFI Terminator X ECU.

On 93-octane pump gas — this aluminum 427 is a street engine after all, not a race engine —The engine is hard-limited to 6,400 to maintain component longevity. So, the dyno sweep was set for 3,300 to 6,400, and they let it eat. The result was 593.1 horsepower and still climbing at 6,400 rpm with 531.9 lb-ft of torque at 4,700 rpm. And, Huneycutt points out, Prestige doesn’t chase numbers. Otherwise, it would have been easy to just turn a hundred or two extra RPM to break the 600-horsepower mark.

This engine is stout. Almost 600 horsepower naturally aspirated, and with the 6,400-rpm rev limit in place, this thing should last for quite a long time. Nothing like power and reliability for your street car.