How to Properly Break In SBC 406 Engine

The SBC 406 engine is a popular choice for many hot rod enthusiasts. It has a high-performance and powerful reputation, but it’s also known for being hard on the valves. If you’re planning on using an SBC 406 engine in your car or truck, it’s important to know how to properly break in your new engine before you put it into service.
The first step to properly break in an SBC 406 engine is to make sure that all of its parts are installed correctly and working properly together as one unit. This includes checking all gaskets, seals and bearings; tightening bolts; cleaning oil passages; ensuring that no debris has gotten trapped anywhere. Once everything looks good on paper–and after doing so many times over–you can begin actual operation testing by starting up at low rpm until warm then gradually increasing speed until reaching full throttle at redline (or whatever speed works best for you).

Preparing the SBC 406 for Break-in

break in sbc 406 engine

Before you can break in your engine, it’s important to properly prepare the engine. This includes installing the correct oil filter and checking and adjusting valve lash. You should also check for any leaks in your cooling system, as well as inspect all hoses for damage or cracks that could cause leaks later on down the road.

Adding High-Quality Oil

  • Use high-quality oil.
  • Change the oil at the recommended intervals.
  • Use the right amount of oil in your engine, which is typically 3-4 quarts for a stock SBC 406 engine.

How do you break in the SBC 406 Engine?

The first step to break in the SBC 406 is to start the engine. Next, increase RPMs slowly until you reach about 2,000 rpm (revolutions per minute). Then hold that speed for 30 seconds while varying load on the engine by increasing or decreasing throttle position. After this warmup period has passed, gradually increase speed and load until you reach 5 mph before returning back down again at 5 mph until you reach idle speeds again–this will help ensure proper break-in of all components within your SBC 406 engine!

Importance of Breaking in the Camshaft Properly

The camshaft plays a critical role in the engine’s operation. It opens and closes the valves, allowing air and fuel to enter and exhaust gases to exit the combustion chamber. As such, it requires special attention during the engine’s break-in period. The camshaft’s lobes and lifters need time to wear in and form a proper mating surface. High RPMs or excessive loads during the break-in process can cause premature wear on the camshaft, leading to poor engine performance or even failure. Taking care of the camshaft during the break-in period ensures that the engine runs smoothly and performs at its best. If you’re in need of a new camshaft, review our guide on the best cams for SBC 406.

Post SBC 406 Break-In Maintenance

After you’ve broken in your new SBC 406 engine, it’s important to make sure that everything is working properly. This includes changing the oil and filter, checking valve lash and inspecting for any issues.

Drive Carefully

After the SBC 406 break-in period, you should drive your car carefully. You don’t want to stress the engine by driving it at high speeds or accelerating too quickly.


In conclusion, before using the SBC 406 engine, ensure that it has been assembled correctly and all parts are functioning properly. It’s crucial to break in the engine appropriately to get the best performance out of it.

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