ATK Marine DMX1 Chevy 4.3L V6 Roller Rebuilt Long Block Crate Engine

Description

Propel recreational runabouts with the ATK Marine DMX1 Crate Engine in rebuilt roller long block trim. Displacing 262 cubic inches across 4.3 liters, this marine Chevrolet V6 produces 225 horsepower at 4,800 RPM and 275 lb-ft torque at 3,400 RPM. Outfitted with brass freeze plugs and hydraulic roller valvetrain components, it equips boaters with fuel-efficient aquatic thrust.

A precision-machined cast iron GM 4.3L V6 block features an internal balance shaft and brass core plugs to resist harsh raw-water corrosion. The rotating kit pairs a nodular cast iron crankshaft with forged connecting rods and 9.4:1 marine pistons inside 4.000-inch bores. Stroke measures 3.480 inches, supported by a 1-piece rear main seal and a marine-baffled steel oil pan for wave protection.

Key Features of ATK Marine DMX1

Sterndrive technicians choose to buy ATK Marine DMX1 crate engine packages to drop modernized V6 power into hulls without modifying stringer engine perches. This long block package fits MerCruiser, Volvo Penta, and OMC 4.3L sterndrive craft.

• Vortec high-swirl combustion chambers accelerate intake flame travel to maximize cylinder fill efficiency and torque.
• Internal balance shaft reduces cabin vibration to keep hull cruising smooth throughout extended lake outings.
• Hydraulic roller camshaft profiles reduce valvetrain friction while sustaining broad power across prolonged cruising runs.
• 1.94-inch intake and 1.50-inch exhaust valves flow dense air charges to lift small boats onto plane with speed.
• Brass core plugs pressed into block water jackets stop electrolytic corrosion during long dock mooring periods.
• ATK Marine DMX1 rebuilt units feature modern 1-piece rear main seals to stop oil loss into boat bilges.
• Marine-grade composite cylinder head gaskets withstand high combustion pressures in unpressurized raw-water cooling systems.
• Marine oil pan configuration retains crankcase oil volume during sustained boat planing angles and steep chop.

Dyno Profile Valvetrain Behavior

This 4.3L Vortec marine engine produces 225 brake horsepower at 4,800 RPM and 275 lb-ft torque at 3,400 RPM across an effective 1,800 to 4,800 RPM band. Compression operates safely on standard 87-octane marine gasoline. The marine camshaft profile preserves 17 in-Hg manifold vacuum at 750 RPM to support marine shift interrupters. Hot engine oil pressure registers between 40 and 60 PSI.

Chassis Clearances Bellhousing Integration

External envelope dimensions follow traditional GM V6 marine architecture, seating between narrow boat bilge stringers without modification. The crankshaft tail accepts late-model 4.3L marine flywheels and drive couplers for sterndrive units. Motor mount points accept factory adjustable marine stringer mounts without exhaust Y-pipe interference.

Break-In Protocol Maintenance Limits

Spin the internal oil pump with an external pre-lube drive tool until mechanical pressure gauges indicate oil arrival at the rocker arms. Fill the sump with conventional 10W-30 petroleum break-in oil enriched with zinc additives before starter engagement. This marine-grade engine is engineered for aquatic propulsion but is not designed for automotive chassis without marine exhaust or supercharged boost past 5 PSI.

• Replace the break-in motor oil and spin on a marine-grade oil filter after the first 20 operating hours.
• Inspect flame arrestor clean condition and check marine manifold water jackets every 50 hours of operation.
• Examine raw water pump impellers and inspect marine engine zinc anodes every 12 months or 100 operating hours.

Warranty Statement Shipping Manifest

ATK covers this marine power package with a 12-Month factory warranty against defects in materials and craftsmanship. The secure wooden crate holds the assembled marine long block, cast iron Vortec cylinder heads, timing cover, marine oil pan, valve covers, instruction manual, and official dynamometer verification sheet.