New 8.1L Vortec Marine Base Engine (replaces years 2000-Newer)

New 8.1L Vortec Marine Base Engine (replaces years 2000-present)

Not available at this time.

Brand new 8.1L/496 c.i. Vortec Marine Base Engine. This engine will replace those 8.1L marine engines used in Mercruiser, Volvo Penta, OMC, Crusader, Indmar and other applications between the years 2000-present.

It is important that your HP and camshaft match the existing engine that you are replacing. Two different versions of the 8.1L engine were used in marine applications. One, a stock motor getting 375HP, and the other, a High Output "HO" motor getting 420 HP. This item number, 5276NMSR, is for the stock version. If you need the HO version, select the HO option in the dropdown above.

This is a perfect stock replacement for those engines that have suffered from a cracked block due to improper winterization or another type of engine failure.

This "Base Engine" Package includes:

• new engine block, heads and all internal components
• valve covers
• timing cover
• oil pan
• harmonic balancer

Specifications:

• 1 Piece Rear Main Seal
• Standard rotation
• Cylinders: 90 Degree V8 Cylinder
• Hydralic Roller Camshaft
• Bore: Standard
• Oil Type: SAE 15W40 Pennzoil Marine
• Horsepower: 375 hp @ 4600 RPM / 420 hp @ 4600 PRM (High Output)
• Torque: 490 lb-ft @ 3200 RPM

About Our Marine Base Engines

New Marine Engines 4 Less Units

Beginning in 2015, GM has begun to discontinue many of their marine engines. This includes the 3.0L and 4.3L in 2015, the 5.0L in 2016, and the 7.4L and 8.2L in 2022. To date (March 2023), GM only produces the Vortec 5.7L marine engine. Because of this, we began producing our own new units in 2021. These new units use DART’s performance engine blocks and are machined, assembled and tested in our facility. They are built to GM factory specifications and there will be no issues to use these units in place of GM MPI or TBI units.

Similarly, in 2023 Mercruiser’s “Quicksilver” branded engines will begin to use new DART blocks as well, as GM has discontinued and stopped providing new engines to Mercruiser.

The benefit of using our in house produced units using DART engine blocks include:

• Priority main oiling system feeds main bearings first. See Figure 1.
• Siamese cylinder bores with extra thick walls resist cracking and improve ring seal for more power (minimum .275” thick with 4.185” bore).
• Open lifter valley improves oil return to pan.
• Blind head bolt holes don’t go through to water jacket.
• Billet steel 4-bolt main bearing caps on all 5 mains.

Figure 1: Priority main oiling primes the main bearings first and then to the lifters and top end instead of top down oil priming in OEM blocks allowing for peak performance at high temperatures.