How To Build A 300 Hp Chevy 350


The Chevrolet engine, which has a displacement of 350 cubic inches, has been one of the most commonly used and commercially produced engines in the history of the world. In addition to the vehicle’s relatively low weight, it is not unusual for aftermarket performance components to be easily accessible. This, along with the fact that it is easy to implement upgrades that result in more than 400 horsepower, makes it possible to increase the vehicle’s performance.

In point of fact, when optimised for use in competition, this engine design is capable of producing well over 1.5 horsepower per cubic inch. However, the “top-end” of the engine is the most essential component when it comes to the production of power. This component comprises the cylinder heads, camshaft timing, as well as the intake and exhaust systems.

Making Preparations for the Quick Block

Step 1

  • Verify if the lowest component of the engine is capable of withstanding increased power levels. It is quite unusual for a factory engine of 350 cubic inches of displacement to be designed to produce as much as 300 horsepower or more.
  • Because of their strong performance credentials, higher performance variations of factory engines like those found in vehicles like the Corvette and Camaro often have the highest-rated engines, and as a result, they can be suitable “models” for the basis of a high performance engine because of their increased torque and horsepower.

Step 2:

  • Get in touch with a reputable engine machinist and inquire about the required machining services they offer. It is imperative that you verify that the engine block and all of the internal components are up to the task of managing the additional power.
  • Even while a completely stock lower end (short block) can be sufficient in some circumstances, the factory components might not be durable enough to retain performance when subjected to greater levels of power.
  • Ensure that the engine short block has the correct clearances by performing the relevant checks. Increasing the engine’s revolutions per minute (RPM) will often result in a greater output, and if the engine has acceptable internal specifications and clearances, it will continue to function for a longer period of time even when working at higher rates.
  • Despite the fact that many engines with a displacement of 350 cubic inches are readily capable of producing 400 or more horsepower, one of the numerous internal components that has a high failure rate is connecting rod nuts. This component is just one of the many internal components that has a high failure rate.
  • In addition to the appropriate machining and clearances, an upgrade to the rod bolts may be an extremely cost-effective modification that helps to prevent this sort of common failure.

A Technique for the Acquisition of Air

Step 1:

  • Choose a set of cylinder heads that has been built expressly to meet the demands of the application you will be using. In terms of performance, even the high-performance castings produced by General Motors in the late 1960s and early 1970s are unable to compete favourably with the more modern factory “Vortec” heads.
  • These heads, which were produced in the late 1990s for the 5.7L Vortec engine, feature airflow characteristics that are superior to even substantially modified early GM castings. These heads were created for the Vortec engine. As a consequence of this, they have the potential to sustain more than 400 horse power, providing that the intake, carburetor, and camshaft are well selected.
  • If you are planning to buy a head that is aftermarket, you should stay away from the alternatives that have intake ports that are far too large. As a consequence of this, the performance at low RPMs will be diminished.

Step 2:

  • Select a camshaft for the engine that provides valve timing events that are compatible with the specified operating range of the engine. It is of the utmost importance to steer clear of picking a cam that is unreasonably “big.” Instead, go with a cam that has a measured effective valve opening duration of somewhere in the range of 220 to 235 degrees (AT.050 tappet lift) and roughly.480 to.500 inches of gross valve lift.
  • This will give you the best results. Because of this, we can be confident that the valves will open and close correctly. It is essential to be aware that going over a lift of.460 millimetres on a factory Vortec head will need performing some machining on the valve guide bosses in order to keep the valve retainer-to-guide boss clearance intact.
  • However, this is a machining process that is not overly complicated and may be done at a low cost. It is imperative that you utilise the valve springs that are recommended by the camshaft manufacturer.
  • It is important to select a carburetor and intake manifold that are compatible with one another. Again, you need to choose one that is suitable for the maintenance that will be performed on the engine.
  • An aftermarket dual-plane manifold equipped with a carburetor that has a capacity of between 600 and 750 CFM will be able to give sufficient airflow for a head and cam combination that has been appropriately chosen, and it should also be able to maintain good street drivability.