Remanufactured Gen IV 7.4L, 454 Marine Longblock. Replaces years 1973-1990.

Remanufactured Gen IV 7.4L, 454 CID Marine Longblock. Replaces years 1973-1990

Completely remanufactured 7.4L, 454 CID Gen IV marine engine longblock. The longblock comes assembled with all internal components, cylinder heads, and gasket kit and oil pump. The only components that are remanufactured in this assembly is the engine block, cylinder heads, crankshaft, and connecting rods. All remaining components are new.

• Gen IV 1973-1990
• Block casting numbers: 286,289,321,959,445,293
• Head casting numbers: 236,045,360,241,290
• 2-PC Rear Main Seal
• Hydraulic Flat Tappet Camshaft
• Oval Intake Ports
• Uses 10 Bolt Steel Timing Cover
• Reverse Rotation Available (+$800)

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.

Learn more about or remanufacturing process below.

Our Remanufactured Engines

With our 40 years in the engine business we have learned over years what parts and processes work the most effectively to produce a quality unit. With that information we have a Premiere Multi-Step Method that we use to remanufacture our engines.

Only the Best Blocks:

• We start by selecting only the "healthiest" blocks. No cracks, no rust, no signs of abuse, no signs of salt water use.
• We completely disassemble the blocks and vigorously clean them along with the cylinder heads and crankshafts. We use a thermal cleaning process which includes baking them in an oven to remove core material and running them through a stainless steel shot machine to clean them to machinable metal.
• We then demagnetize the engine blocks before machining them on our CNC machine to insure precise OE specifications.

Figure 1: Here, a line of remanufactured 4.3L engines are being built on one of our three assembly conveyors.

We measure cylinder bores three times:

• As an example of our passion for perfection, after we bore, hone and plateau brush all cylinder walls, we measure them three times to ten-thousandths of an inch.
• Bore sizes will rarely be over .030.
• We know this extra dedication will pay off for you in performance and dependability. 

Figure 2: All of our engine blocks are bored, decked, and blueprinted on CNC equipment. Here, you can see a 5.0L engine block being "probed" so that the bore will be to exact OEM specifications.

Figure 3: Here, you can see a 5.0L block being honed to exact sizing. We use diamond tooling to create pristine cross-hatches for prefect piston ring clearance and function.

New internal parts, marine gaskets:

• We install vital new internal parts, including new hypereutectic (heatfighting) pistons where available, new premium piston ring sets, new engine bearings, new valves, new camshafts, new springs, new lifters, new timing components and new tinware (where applicable).

We also install special marine head gaskets-steel, copper or copper clad, whatever the application demands:

• We always use brass or stainless steel expansion plugs. ALL parts we install meet or exceed original manufacturers' specs. Many parts are actually better than original equipment. We pick up running changes to eliminate problems common in the original engine.

The Final Touch:

• After our expert technicians have completed all critical machining operations and the components have been washed, our assembly team takes over.
• We pre-lubricate camshafts and pistons.
• Once assembled, we spin test every assembled engine on our Sim-Test machine while our technician logs the compression and oil pressure for future reference.
• After a complete final inspection before shipping…your Marine Engines 4 Less remanufactured engine is fully functional and ready to go.

Figure 4: All of our engines, new and remanufactured get SIM tested before shipping. This process involves checking each cylinder to appropriate compression readings, priming the top end valve train and oil pump, inspecting for oil leaks and noises. The helps to insure that the end user gets a quality product free from imperfections and quality issues.