Nitrous oxide remains one of the most efficient ways to add significant horsepower to a street or race engine. The reasons are straightforward: measurable power gains, low cost relative to forced induction, and installation that does not require major engine modifications. For this test, a Zex Perimeter Plate nitrous system was paired with a 347-stroker small-block Ford to quantify the gains on a dyno.
The Engine Build
The foundation is a late-model 5.0-liter block stroked to 347 cubic inches. The rotating assembly includes a 3.40-inch stroker crank paired with 5.40-inch Speedmaster connecting rods and JE forged pistons sealed with Total Seal rings. Up top, CNC-ported ProMaxx aluminum heads and a Comp XFI cam handle airflow. A single-plane Edelbrock Victor Jr. intake and Holley 650 Ultra XP carburetor manage fuel and air delivery. Ignition is handled by an MSD billet distributor and 6AL amplifier.
Baseline Results
Before introducing nitrous, the 347 was run on the dyno with Hooker headers, a Meziere electric water pump, and a Speedmaster neutral damper. The naturally aspirated baseline: 441 horsepower at 6,500 rpm and 405 lb-ft of torque at 5,000 rpm.
How Nitrous Oxide Works
Nitrous oxide (N2O) is an oxidizing agent, not a fuel. When heated to 572 degrees inside the combustion chamber, the compound breaks apart and releases free oxygen molecules. Those molecules support additional combustion when paired with supplemental fuel - gasoline or methanol - producing measurable gains in cylinder pressure and output.
A secondary benefit is charge cooling. Nitrous is stored as a liquid and converts to gas upon injection. That phase change occurs at -129 degrees, absorbing significant heat from the intake tract and incoming air charge. Cooler, denser intake air further supports combustion efficiency.
"As if the extra power wasn't enough, the compound also offers a side benefit in the form of charge cooling."
The Zex Perimeter Plate System
The Zex Perimeter Plate nitrous system was selected for its even distribution pattern and straightforward installation on the 347 build. The plate mounts between the carburetor and intake manifold, delivering nitrous and supplemental fuel through a perimeter-style injection ring.
The Result
With the Zex system activated, the 347 stroker picked up 171 horsepower over the naturally aspirated baseline. That gain came from a single plate system on an engine already producing strong numbers - evidence that a properly matched nitrous setup delivers real, repeatable output on a well-built foundation.
The combination of Speedmaster connecting rods, forged internals, and the Zex Perimeter Plate demonstrates what becomes possible when each component in the system is selected with intention. The 347 was built to handle the additional cylinder pressure, and the nitrous system delivered exactly what the engineering allowed.
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