ATK DM29 Marine Rebuilt Long Block — Chevy 4.3 V6 (262) Marine Engine, 1987–1992
Get back on the water with a zero-hour heart for your sterndrive or inboard. The ATK DM29 is a professionally rebuilt marine engine — the Chevy 4.3L / 262 V6 that powered countless Mercruiser, OMC and Volvo Penta sterndrive packages from 1987 through 1992. Rated at 205 horsepower with a roller camshaft, 1-piece rear seal and standard rotation, this long block arrives with oil pump and gasket installed — ready to receive your marine intake, carburetor or throttle body, exhaust manifolds and accessories. Crated and shipped fast across Europe from NH Race Engine.
Why Choose the ATK DM29 Marine Engine?
A marine engine lives a harder life than its automotive cousin: constant high-RPM cruising, heavy loads, salt or freshwater exposure and long idle periods in humid bilges. That’s why dropping a car engine into a boat is a false economy — marine engines need marine-grade rebuilds with the right cam timing, gaskets, corrosion protection and rotation for your drive.
The DM29 is built specifically for boating applications. ATK starts with a sound Chevy 4.3L / 262 V6 core from the correct 1987–1992 standard-rotation family (block castings 011, 867, 683), then rebuilds it to factory marine specification: 205 horsepower, roller camshaft for modern durability, 1-piece rear main seal and a fuel pump mounting provision. Oil pump and gasket are included, and every engine is tested before crating. This is the smart alternative to a used marine pull with unknown hours and salt-water history — or a new complete engine at three times the price.
Key Features & Benefits
- Marine-Specific Build: Engineered for boating applications — not a converted automotive block. Correct rotation, cam and sealing for sterndrive and inboard duty.
- 205 Horsepower: Factory-rated output matching the original 1987–1992 4.3L marine V6 — your boat performs exactly as designed.
- Roller Camshaft: Modern roller cam for better durability at sustained cruise RPM — the marine engine’s toughest workload.
- Standard Rotation: Fits 1987–1992 standard-rotation applications — verify against your drive unit (Mercruiser Alpha/BRAVO, OMC Cobra, Volvo Penta) before ordering.
- 1-Piece Rear Main Seal: Modern sealing technology against the bilge environment where leaks matter most.
- Fuel Pump Hole Provision: Correct mechanical fuel pump mounting as per the original marine configuration.
- Cast Iron Block & Heads: Durable, corrosion-tolerant marine architecture — castings 011, 867, 683, 2-bolt mains.
- Oil Pump & Gasket Included: Ready for priming at installation — one less marine-grade part to source.
- Rebuilt & Tested: Professionally rebuilt by ATK with pre-dispatch testing and crating for safe transport.
Boat & Drive Fitment — DM29 Applications
The ATK DM29 marine engine long block is the correct replacement for 1987–1992 sterndrive and inboard packages running the Chevy 4.3L / 262 V6:
- Mercruiser 4.3L installations: Alpha One and Bravo drive packages — standard rotation applications
- OMC Cobra / King Cobra 4.3L installations
- Volvo Penta 4.3L installations: AQ-series standard-rotation packages
- Repower Projects: Ski boats, bowriders, cuddy cabins and runabouts originally equipped with the 4.3 V6
Verify before ordering: Marine engines come in standard and reverse rotation depending on drive configuration, and the 4.3 family spans multiple eras with different seals, cams and castings. The DM29 covers 1987–1992 standard-rotation applications (castings 011, 867, 683). Send us your engine serial number, drive model or casting numbers and our technical team will confirm the DM29 is the exact match — or identify the correct ATK code if it isn’t.
Technical Specifications
| Part Type: | Marine Engine — Long Block (Rebuilt) |
| Product Line: | ATK Marine Rebuilt Long Block Engines |
| MPN: | DM29 |
| Engine Family: | Chevrolet 4.3L / 262 cu in V6 |
| Horsepower: | 205 HP |
| Configuration: | V6, OHV, cast iron block & heads |
| Camshaft: | Roller cam |
| Rotation: | Standard |
| Rear Main Seal: | 1-piece |
| Model Years: | 1987–1992 |
| Block Castings: | 011, 867, 683 |
| Main Bearings: | 2-bolt mains |
| Fuel Pump Hole: | Provision included |
| Oil Pump & Gasket: | Included |
| Air Cleaner / Carburetor: | Not included — transfer from original |
| Assembled: | Yes — sold individually |
What’s Included vs. What You Transfer
| Component | Included | Transfer from Original Engine |
|---|---|---|
| Engine block (rebuilt) | ✅ | — |
| Crankshaft, pistons, rods, bearings | ✅ | — |
| Cast iron cylinder heads & valvetrain | ✅ | — |
| Roller camshaft & timing components | ✅ | — |
| Oil pump & gasket | ✅ | — |
| Marine intake manifold | — | ✅ |
| Carburetor / throttle body | — | ✅ |
| Marine exhaust manifolds & risers | — | ✅ |
| Ignition distributor & coil | — | ✅ |
| Oil pan (marine) | — | ✅ |
| Valve covers & timing cover | — | ✅ |
| Sea water pump & circulation pump | — | ✅ |
| Harmonic balancer | — | ✅ |
| Flexplate / flywheel | — | ✅ |
| Engine mounts & coupler | — | ✅ |
Rebuilt vs. Used Marine Pull — Comparison
| Feature | ATK DM29 Rebuilt | Used Marine Pull |
|---|---|---|
| Known hours & history | ✅ Zero-hour rebuild | ❌ Unknown, often salt-water |
| Correct marine rotation & cam | ✅ Guaranteed | ❌ Verify yourself |
| New gaskets & seals throughout | ✅ | ❌ |
| Machine work to spec | ✅ | ❌ |
| Tested before crating | ✅ | ❌ |
| Warranty support | ✅ ATK warranty | ❌ None |
Frequently Asked Questions
Is the ATK DM29 a drop-in replacement for my Mercruiser 4.3?
Yes — for 1987–1992 standard-rotation Mercruiser 4.3L packages. Transfer your marine intake, carburetor or throttle body, exhaust manifolds and risers, ignition, sea water pump, oil pan, balancer, flexplate and coupler from the original engine. Verify rotation and casting numbers with our team before ordering.
How do I know if I need standard or reverse rotation?
Rotation depends on your drive unit and engine pairing — twin-engine boats often mix both. Check your engine serial number or drive model (Mercruiser, OMC, Volvo Penta) and send it to us — we’ll confirm which rotation your application needs.
Does the DM29 include the carburetor, exhaust manifolds and sea water pump?
No — this is a long block. It includes the assembled block, cast iron heads, roller cam valvetrain, oil pump and gasket. Marine intake, carburetor or throttle body, exhaust manifolds and risers, ignition, oil pan, valve covers, sea water pump, balancer and flexplate transfer from your original engine.
Is a rebuilt 4.3 marine engine worth it versus a new engine?
For a sound hull with tired power, absolutely — a rebuilt long block typically costs a fraction of a new complete marine engine, and the 4.3 V6 has decades of proven marine service with parts available everywhere. The savings usually leave budget for the marine installation parts that matter: new manifolds, risers, pumps and gaskets.
Can you help me identify my marine engine?
Yes — send us your engine serial number, drive model (e.g., Mercruiser Alpha One), or photos of the casting numbers and ID tag. Our technical team identifies marine applications daily.
Recommended Companion Products
- Complete marine installation gasket set
- Marine break-in oil & assembly lubricant
- Sea water pump & circulation pump
- Marine exhaust manifolds & risers
- Marine distributor, coil & plugs
- Marine engine mounts & hardware
- All remanufactured & rebuilt engines
What Does It Fit?
Condition & Pre-Delivery Inspection
-
Rebuild process: cleaned, crack-tested, machined to spec, renewed wearable parts, dyno-verified
-
Our inspection on arrival in Kessel: crate integrity, rotation confirmation, sealing caps intact, casting numbers checked
-
Your installer should: fit new manifolds gaskets, renew the seawater circulation pump and thermostat housing (cheap insurance against the #1 marine cooling failure), use marine-grade oil, and follow the first-start and break-in guidance in our installation guides
-
Register your warranty on our warranty registration page
Recommended Companion Products
-
Browse the Marine Engines range [VERIFY slug] — Yanmar diesels and more
-
Marine drivetrain: Marine Gearbox range [VERIFY slug — Advance gearboxes in stock]
-
Marine engine service [VERIFY — servicing, installation and commissioning]
-
Core exchange — ask about returning your old block to reduce the price
Reviews
There are no reviews yet.