Nitrous-Fed 427 Cubic-Inch Small-Block Ford Makes 4-Digit Power

It’s no secret that we appreciate a big-power small-block here at EngineLabs, especially if they have a blue oval on the valve cover. So it only stands to reason that we are incredibly interested in this 351 Windsor-based engine build from Prestige Motorsports. Built at the request of Holley for a giveaway promotion they conducted earlier in the year, this build had a very loose set of design parameters: make 1,000 horsepower on nitrous with a small-block Ford. Prestige was weapons-free beyond that.

1,000 horsepower on nitrous isn’t exactly revolutionary in the performance world, but it isn’t child’s play, either, especially when it comes to a small-block Ford. The amount of nitrous that will need to be injected is significant, since Prestige decided to keep the naturally-aspirated combination on the streetable side of things. However, more on how they accomplished that later in the article.

Deceptively Simple Short-Block

When you say “Windsor” and “big-power” in the same sentence, often times the words “split block” pop up. While the fabled 500 horsepower “limit” is usually applied to the shorter-deck 302 blocks, the factory 351 block isn’t generally regarded as able to take too much more power. So, in order to alleviate any whiff of doubt about the stability of the enigne’s foundation, the team chose one of World Products’ Man O’ War 9.5-inch deck iron blocks as the base of the build.

Starting with a new iron alloy, the Man O’ War adds strength through increased material in key areas, like reducing the main cap fastener size from 1/2-inch to 7/16-inch diameter in order to beef up the material around the fastener. Additionally, the Man O’ War can accept a larger 4.125-inch bore, has two extra head bolts per cylinder and has extended cylinder bores that can accept up to a 4.250-inch stroke.

The OEM blocks found on the Windsor family aren't generally regarded as the right choice to make 1,000 horsepower with. To alleviate any concerns, a World Products Man O' War block was used, which easily accommodated the 4.125-inch bore and 4.00-inch stroke. The extended bores did require notching for the rotating assembly as you can see on the right.

Being dropped into the billet mains of the block is a 4.00-inch stroke, internally balanced Eagle crankshaft. Made from forged 4340 steel, the eagle crankshaft should easily hold up to the target power, especially without any external balancing required. Attached to the crank are a set of Eagle H-beam connecting rods. Made from the same forged 4340 steel as the crank, the 6.250-inch long rods use ARP2000 rod bolts and are a solid balance of weight and strength.

Hanging off of the connecting rods is a set of 4.125-inch forged pistons from DSS Racing. The 1.280-inch compression height is needed to fit the 6.250-inch rods, but isn’t so extreme that the wrist pin bore cuts into the oil control ring groove. The ring pack measures in at 1.2mm, 1.5mm, 3.0mm, and the 22cc reverse dome on the piston helps keep compression to a streetable level.

Oil is supplied by a Melling M-83HV high-volume oil pump from Melling, along with a Canton pickup tube designed to match the fabricated steel “road race” style oil pan the project is using. The pan required some minor clearancing of the number five main cap but that was only a minor hiccup.

A set of forged DSS X-skirt pistons were used along with an Eagle forged 4.00-inch stroke crankshaft and 6.250-inch H-beam connecting rods to get the 427 cubic-inch displacement.

An Impressive Top End

Topping off the short-block is a set of AFR’s Renegade 220cc cylinder heads sealed by Cometic MLS head gaskets. The Renegades retain the stock 20-degree inline valve configuration, but with upgraded 2.100-inch stainless steel intake valves, and 1.600-inch Inconel exhaust valves, to handle the intense combustion heat. The 58cc combustion chambers have been completely CNC profiled, along with the 220cc intake port and 70cc exhaust port. AFR advertises the flow of these heads as 325cfm intake, 249cfm exhaust, at .700-inch valve lift.

Controlling the valve events is a solid-roller camshaft from Comp Cams. With .431 inch of lobe lift on the intake and .430 inch on the exhaust, that translates to .690 inch of lift at the intake valve and .688 inch at the exhaust valve. Duration comes in at 260 degrees at .050 inch, intake, and 274 degrees exhaust with a 114-degree lobe separation angle. A Liberty double roller timing set keeps everything in time with the crankshaft, and an SFI-approved, aluminum, neutral balanced Innovator’s West damper keeps the vibrations in check.

The AFR Renegade 220cc cylinder heads came equipped with valvesprings good to 7,400 rpm and .710 inch of valve lift. This combination used almost all of that capability.

A set of BAM solid roller lifters translate camshaft motion into rocker arm motion, via a set of 5/16-inch diameter, .080-inch wall-thickness hardened pushrods, which act on a set of Scorpion Endurance-series aluminum roller-rockers in the factory 1.6:1 ratio. A set of AFR’s dual valvesprings maintain control of the valves with approximately 220 pounds of pressure on the seat. AFR says these springs are good for a maximum lift of .710 inch and are good to 7,400 rpm.

Sitting atop the engine is one of Holley’s 9.5-deck hi-ram intakes, but instead of a more traditional Ford side inlet, or even forward-facing inlet, Prestige opted for a dual-4150 lid. Into the runners, Prestige installed a set of Accel 80 lb/hr injectors. The larger injectors are sized to be able to add the extra fuel needed for the nitrous system being used on this engine.

As was mentioned, this project will use two of Holley’s 1,000-cfm 4150 throttle bodies, which means two nitrous plates. However, the NOS Big Shot plates will only have the nitrous side plumbed, as the Terminator-X ECU will be controlling the fuel enrichment through the main fuel injectors. The Terminator will also be controlling the nitrous solenoids through the built-in progressive nitrous controller, capable of pulsing the solenoids to control the flow of nitrous between 0 and 100-percent.

On the left, you can see the two NOS Big Shot single-bar nitrous plates being fitted to the manifold. On top of those, a pair of 4-barrel 4150-style throttle bodies were fitted to provide as straight a shot into the engine as possible.

For the test, a .073-inch orifice nitrous jet was fitted into each plate, which are both fed by a single Big-Shot nitrous solenoid, which should be good for approximately 400 horsepower-worth of nitrous oxide. However, the nitrous will be ramped in and throttled electronically to reach the target horsepower number, instead of the traditional jet-changing to alter the power output of the nitrous system.

Before spraying the engine, the Prestige Motorsports team made a couple of naturally aspirated dyno pulls to get a baseline number. For the N/A pulls, the run was started at 4,000 rpm and stopped at 7,200 rpm. The peak all-motor horsepower was 631.7 horsepower at 6,900 rpm and peak torque of 521.9 lb-ft at 5,400 rpm.

After some quick nitrous tuning, the ramp built in the Terminator’s controller started with 25-percent nitrous activation at 5,000 rpm, and then steadily ramping up to a peak of 75-percent at 6,000 rpm, and holds there for the duration of the run. That ramp provided a peak power number of 1,001.2 horsepower at 6,600 rpm and peak torque came it at 5,600 rpm, measuring 898.6 lb-ft. And the best part about those numbers, is that there is still another 25-percent left with the currently installed .073 jets. So even more power is just a few keystrokes away.

As you can see, the design goals set forth for the engine were a complete success. Making 632 horsepower and 522 lb-ft of torque naturally aspirated, and 1,001 horsepower and 899 lb-ft of torque on only 75-percent of a 400-shot of nitrous is not only impressive, but means there’s still another 25-percent of nitrous oxide only a few keystrokes away.

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About the author

Greg Acosta

Greg has spent fifteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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