Replacing Your 7.4 Liter Marine Engine Long Block
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TERMINOLOGY: There are three different types of marine 7.4L 454 cid engines. Some of the engines are interchangeable and with only a few changes. NEW long block engines are available only for 1987 and up big block engines. If you are replacing a pre-1987 "Mark IV" engine and you are looking for a direct replacement you will need to purchase a remanufactured long block.
There are many difficulties involved with Big Block V8 re-powers today since all of the marine engine manufacturers quit offering complete turnkey 454's several years ago, and now that the 496's were discontinued from GM in 2010. The remaining inventory on the 496’s is getting extremely low and expected to be completely depleted within the next 6 months. All of this limited engine availability in combination with the new 2010 emissions rules creates a more complicated re-powering situation to say the least.
7.4L L29 MPI 1998-2001 NEW Longblock This long block engine was used only with a General Motors installed multi-port injection (MPI) fuel delivery system. The long block utilizes a 1 piece rear main seal, roller camshaft, and oval port heads. The engine is rated at 330 hp but is not an actual produced power number. The actual horsepower value is about 305 hp. The engine does not include the intake, flywheel, and water pump. You must use an electric pump.
7.4L 330HP Power Package PPT introduces the 7.4L Power-Pack, the re-power package that gives you what you need. This Power-Pack is a NEW 330 horsepower GM Gen V/VI base engine, equipped with a complete fuel system as well as the ignition system. By using existing hardware, bell housing and exhaust systems, installation is made simple.
7.4L 330hp 1987-2002 NEW Longblock This long block engine was used with a 4 BBL carburetor, EFI (throttle body), and a Mercruiser factory installed multi-port injection (MPI) fuel delivery system. It has a 1 piece rear main seal, roller camshaft, and oval port heads. This engine can be used for pre-1987 applications but a modification must be made for the electric fuel pump. The engine does not include intake, flywheel, or water pump.
454 MAG 385 hp 1987-2002 NEW Longblock This is the best way to distinguish it from the other 7.4L engines is that it has rectangular port heads and a high performance camshaft. They are the same heads that are used in the 8.2L 502 cid engine. The engine has a 1 piece rear main seal, roller camshaft, and must use an electric a fuel pump. The engine does not include an intake, flywheel, or water pump.
454 MAG 392 Hp Power Package This Power-Pack is the perfect repower option for pre-1992 base 7.4L applications or for even for 1992 and up applications looking to upgrade from a 310/330HP 7.4L to the higher HP and higher torque 454 MAG 392 HP engine. Equipped with a complete fuel system as well as the ignition system. By using existing hardware, bell housing and exhaust systems, installation is made simple.
502 MAG 415 Hp NEW Longblock This engine uses the same heads that are used with the 7.4L 454 cid magnum engine (rectangular intake port). The engine has a 1 piece rear main seal, roller camshaft, and must use an electric a fuel pump. The engine does not include an intake, flywheel, or water pump.
502 MAG 415 Hp Power Package This Power-Pack is the perfect repower option for pre-1992 base 7.4L or 502 applications or for even for 1992 and up applications looking to upgrade from a 310/330HP 7.4L to the higher HP and higher torque 502 MAG 415 HP engine. Equipped with a complete fuel system as well as the ignition system. By using existing hardware, bell housing and exhaust systems, installation is made simple.
PPT also offers Remanufactured 7.4L Big Block Marine Engines
Partial Engine Packages (Longblock + Carburetor + Ignition)
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