What is a 350 Bored .60 Over?
This phrase refers to an engine modification, specifically related to increasing the displacement (size) of a small-block Chevrolet 350 cubic inch engine. Let's break down what each part means:
350: This refers to the original cubic inch displacement of the engine block. The 350 small-block Chevy is a legendary engine known for its performance and reliability. Cubic inch displacement is a measure of the total volume of all the cylinders in an engine.
.60 Over: This signifies that the engine's cylinders have been bored out by 0.60 inches (or 60 thousandths of an inch) in diameter. Boring is a machining process that enlarges the cylinder's diameter. This increased diameter allows for the use of larger pistons, increasing the engine's displacement and thus power output.
Therefore, a "350 bored .60 over" describes an engine that started as a 350 cubic inch engine but has undergone cylinder boring to increase its size. The exact increase in displacement from a .60 overbore depends on the engine's original specifications and the piston's design, but it typically results in a noticeable bump in horsepower and torque. This is achieved because the larger cylinders allow for a larger volume of air-fuel mixture to be burned during each combustion cycle.
What are the implications of a .60 overbore?
A .60 overbore isn't simply about getting more power; it also involves several considerations:
- Increased Displacement: This is the primary benefit – a larger displacement means a larger explosion in each cylinder, yielding more power.
- Cylinder Wall Thinning: Boring the cylinders reduces the thickness of the cylinder walls, potentially making them weaker and more susceptible to damage. This highlights the importance of using high-quality engine parts and performing a proper rebuild.
- Piston Choice: Choosing the right pistons is crucial. They need to fit the bored cylinders perfectly to prevent wear and tear.
- Potential for Problems: Excessive boring can lead to engine problems, including decreased longevity and potential for cracking or failure if done improperly. A skilled machinist is essential.
- Need for Replacement Parts: You'll likely need new pistons, rings, and potentially other components, as the old ones won't fit the enlarged cylinders.
How much does a .60 overbore increase displacement?
The exact increase in displacement from a .60 overbore on a 350 cubic inch engine isn't a fixed number. It depends on factors such as the stroke of the crankshaft and the design of the pistons. However, a .60 overbore typically results in a few extra cubic inches of displacement, usually around 5-10 cubic inches, moving the engine's displacement to somewhere in the range of 355-360 cubic inches.
Is a .60 overbore always the best option?
No, a .60 overbore might not always be the ideal choice. The decision depends on the condition of the engine block, the desired performance goals, and the budget. Multiple overbores can weaken the block, and there's a limit to how much you can bore an engine before it becomes structurally unsound. A professional engine builder can advise on the best course of action based on the specific circumstances.
This detailed explanation should give a thorough understanding of what a "350 bored .60 over" signifies within the context of automotive engine modifications. Remember to consult with experienced engine builders and machinists for any engine work.
