Transform your classic Ford with serious small-block performance. The ATK HP100M Stage 2 347ci stroker V8 delivers a dyno-proven 450 horsepower and 440 lb-ft of torque from the compact, proven architecture of Ford's legendary small block V8.
Product Overview - ATK HP100M
This isn't simply a warmed-over 302. ATK builds the HP100M around a seasoned OE roller block and increases displacement to 347 cubic inches with a 3.400-inch-stroke SCAT nodular-iron crankshaft, SCAT 4340 forged I-beam connecting rods, and forged flat-top pistons. Up top, a pair of Dart Pro 1 aluminum cylinder heads and a performance hydraulic roller camshaft give the stroker the airflow and valve action necessary to produce 450 horsepower while retaining the familiar packaging advantages of a Ford small block.
The result is an impressive powerplant for enthusiasts who want the displacement, torque, throttle response, and horsepower of a purpose-built performance engine without abandoning traditional Ford small-block architecture.
Better still, the HP100M comes in ATK's Stage 2 Mid Dressed configuration. In addition to the oil pump, oil pan, timing cover, and valve covers supplied with a Stage 1 engine, Stage 2 adds a distributor, performance intake manifold, water pump, flexplate, and harmonic balancer. Install the appropriate carburetor, spark plugs, and ignition wires of your choice to complete the package.
Whether you're building a muscular Mustang street machine, a Pro Touring Ford, a vintage restomod, or simply want considerably more punch from your classic, the HP100M brings together premium performance hardware and a potent 347-cubic-inch combination.
Features, Advantages & Benefits
347 Cubic Inches of Stroker Performance
Feature: The HP100M increases traditional Ford small-block displacement to 347 cubic inches with up to a 4.040-inch bore and a 3.400-inch stroke.
Advantage: The longer stroke increases displacement without requiring a physically larger big-block engine.
Benefit: More displacement helps produce the strong torque and horsepower enthusiasts want while retaining the compact packaging characteristics that make the Ford small block so popular.
Dyno-Proven 450 Horsepower
Feature: ATK rates the HP100M at 450 horsepower and identifies the engine as dyno-proven.
Advantage: The engine is offered as a developed performance combination rather than leaving the customer to assemble and match individual internal components.
Benefit: You get serious, documented performance potential straight from the crate—enough power to completely transform the character of a classic Ford.
440 LB-FT of Torque
Feature: The 347 produces 440 lb-ft of torque.
Advantage: The stroker's added displacement produces the kind of torque that makes a performance street car feel powerful beyond the peak horsepower number.
Benefit: Expect authoritative acceleration and the satisfying low- and mid-range punch that makes a high-performance V8 so much fun on the street.
SCAT 3.400-Inch Stroker Crankshaft
Feature: A SCAT nodular-iron crankshaft with a 3.400-inch stroke forms the heart of the rotating assembly. The crankshaft uses a one-piece configuration with 28-ounce external balance.
Advantage: Increasing stroke is what turns the traditional small-block Ford combination into a 347-cubic-inch performance engine.
Benefit: The added displacement contributes directly to the engine's impressive 450-horsepower and 440-lb-ft output while maintaining small-block Ford dimensions.
SCAT 4340 Forged I-Beam Connecting Rods
Feature: The HP100M uses 5.400-inch SCAT 4340 forged I-beam connecting rods with ARP 8740 bolts.
Advantage: Forged 4340 rods and quality fasteners provide a substantial performance-oriented foundation for the rotating assembly.
Benefit: The customer gets upgraded internal hardware appropriate to a serious high-performance stroker rather than basic stock-style connecting rods.
Forged Flat-Top Pistons
Feature: The rotating assembly incorporates forged flat-top pistons with four valve reliefs and moly rings.
Advantage: Forged pistons are well suited to the increased cylinder pressure and operating demands of a high-output naturally aspirated engine.
Benefit: Premium piston construction provides added confidence when putting the HP100M's 450 horsepower to work.
Dart Pro 1 Aluminum Cylinder Heads
Feature: The HP100M breathes through Dart Pro 1 aluminum cylinder heads featuring 58cc combustion chambers, 195cc intake runners, and 2.02-inch intake / 1.60-inch exhaust valves.
Advantage: High-flow performance heads allow the 347-cubic-inch bottom end to move the volume of air required to support serious horsepower.
Benefit: Better breathing helps turn the additional displacement into usable power, giving the engine the airflow capability needed for its 450-horsepower rating.
Hydraulic Roller Camshaft
Feature: A performance hydraulic roller camshaft provides .544-inch intake and .565-inch exhaust lift, with 231-degree intake and 235-degree exhaust duration at .050-inch lift.
Advantage: The camshaft is sized to take advantage of the engine's displacement and high-flow aluminum cylinder heads, while hydraulic roller architecture eliminates the periodic lash adjustment required by a mechanical camshaft.
Benefit: The combination delivers the aggressive breathing characteristics expected from a 450-horsepower stroker with a valvetrain architecture well suited to a performance street engine.
Billet Aluminum Roller Rocker Arms
Feature: The valvetrain incorporates 1.6-ratio billet aluminum roller rocker arms.
Advantage: Roller rocker arms reduce sliding friction at the valve tip and complement the engine's hydraulic roller cam and performance cylinder heads.
Benefit: Customers receive a more complete performance valvetrain instead of having to upgrade basic stamped-steel rocker arms after purchase.
10.1:1 Compression Ratio
Feature: The HP100M uses a 10.1:1 compression ratio.
Advantage: The compression ratio is engineered to complement the cylinder heads, camshaft, displacement, and naturally aspirated performance combination.
Benefit: It helps the 347 produce impressive power while remaining compatible with readily available premium pump gasoline.
Designed for 91+ Octane Pump Gas
Feature: ATK recommends 91-octane or higher fuel.
Advantage: Despite producing 450 horsepower, the engine does not require dedicated racing fuel under ATK's stated fuel specification.
Benefit: Fill it with premium pump gas and enjoy serious naturally aspirated V8 performance without the inconvenience and expense of sourcing race fuel.
Stage 2 Mid Dressed Package
Feature: ATK's Stage 2 package includes the oil pump, 5-quart front-sump oil pan, timing cover, valve covers, distributor, performance intake manifold, water pump, flexplate, and harmonic balancer.
Advantage: Many major external components have already been selected for the engine instead of leaving the customer with a bare long block.
Benefit: Less parts chasing, fewer component-selection decisions, and a more direct path toward completing the installation.
Performance Hardware at a Glance
Displacement: 347 ci
Horsepower: 450 HP
Torque: 440 LB-FT
Engine Type: Ford small block V8
Block: Seasoned OE roller block
Bore / Stroke: Up to 4.040" x 3.400"
Crankshaft: SCAT nodular iron, 3.400" stroke
Balance: 28 oz. external
Connecting Rods: SCAT 4340 forged I-beam, 5.400"
Rod Bolts: ARP 8740
Pistons: Forged flat-top with four valve reliefs
Rings: Moly
Cylinder Heads: Dart Pro 1 aluminum
Combustion Chambers: 58cc
Intake Runner: 195cc
Valves: 2.02" intake / 1.60" exhaust
Camshaft: Hydraulic roller
Cam Lift: .544" intake / .565" exhaust
Duration @ .050": 231° intake / 235° exhaust
Rocker Arms: Billet aluminum 1.6-ratio roller
Compression: 10.1:1
Recommended Fuel: 91+ octane
Recommended Total Ignition Timing: 34°–36°
Recommended Automatic Stall Converter: 2400–2800 RPM
Oil Pan: 5-quart front sump
Warranty: 24 months / unlimited mileage
Dyno Proven: Yes
Why a 347 Stroker?
There's a reason the 347 has become one of the most desirable combinations in the small-block Ford world: displacement without giving up the compact small-block package.
A traditional 302 uses a 3.000-inch stroke. The HP100M's 3.400-inch-stroke crankshaft, combined with its increased bore, brings displacement to 347 cubic inches. That means substantially more swept volume while retaining Ford small-block architecture.
For the enthusiast, the payoff is straightforward: more torque and more horsepower from a compact package.
And ATK hasn't relied on displacement alone. The stroker rotating assembly is paired with Dart Pro 1 aluminum heads, large 2.02/1.60-inch valves, a hydraulic roller camshaft, roller rockers, and 10.1:1 compression. It's an integrated combination designed to move air and turn those extra cubic inches into real performance.
Video: Dyno Proven
Built for the Enthusiast Who Wants More
The HP100M occupies an appealing position between an ordinary replacement engine and an all-out racing powerplant.
Its 450 horsepower provides more than enough muscle to turn a classic Mustang or other compatible Ford into a seriously quick street machine. Its 440 lb-ft of torque gives the engine the muscular response expected from a stroker. And because ATK recommends readily available 91+ octane pump gasoline, enjoying that performance doesn't require keeping cans of racing fuel in the garage.
For an automatic-transmission application, ATK recommends a 2400–2800 RPM stall converter, another indication that this is a genuine performance combination intended for enthusiasts looking for substantially more than stock behavior.
Stage 2 Means More of the Engine Is Already Done
A high-performance engine swap requires more than a long block, and that's where the HP100M's Stage 2 Mid Dressed configuration adds considerable value.
ATK starts with the Stage 1 components—oil pump, oil pan, timing cover, and valve covers—and adds the distributor, performance intake manifold, water pump, flexplate, and harmonic balancer.
That means several major components have already been selected and supplied with the engine. The customer can then choose a carburetor, spark plugs, and ignition wires appropriate for the project and desired setup.
The result is a package that offers greater flexibility than a completely dressed engine while eliminating much of the component sourcing associated with starting from a bare long block.
Ideal For
The HP100M is an outstanding choice for:
- High-performance classic Ford street builds
- Mustang restomods and Pro Touring projects
- Enthusiasts replacing a mild 289 or 302 with substantially more power
- Builds where strong naturally aspirated torque is a priority
- Drivers who want 450 HP without stepping up to a physically larger engine family
- Projects where premium internal components are preferred
- Carbureted performance builds
- Enthusiasts who want the flexibility of selecting their own carburetor and final ignition components
Classic Industries lists HP100M fitment for 1965–1996 Ford Mustang applications, including 1974–1978 Mustang II, but vehicle-specific installation requirements must always be verified before ordering.
Installation & Selection Notes
The HP100M is equipped with a five-quart front-sump oil pan, so chassis, steering, and crossmember clearance should be verified for the intended application.
ATK recommends a 2400–2800 RPM stall converter for automatic-transmission installations and 91-octane or higher gasoline.
This is a Stage 2 Mid Dressed engine—not a completely dressed, ready-to-fire package. A carburetor, spark plugs, and ignition wires must still be selected, along with any vehicle-specific accessory-drive, fuel-system, cooling-system, exhaust, electrical, transmission, mounting, linkage, and installation components required by the vehicle.
Computer-controlled vehicles may require updated chips or other modifications. Customers should also verify applicable emissions requirements before installation.
Warranty
The HP100M is backed by ATK's two-year / unlimited-mileage warranty from the date of purchase, providing valuable warranty coverage to accompany its high-performance specification.
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