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Should You Use 4032 Aluminum Forged Pistons or 2618 Aluminum Forged Pistons in your High Performance HEMI Engine?

We decided that it would be good for our customers to understand why they may use one piston over the other in their stroker motor. In this article we want to explain the difference between these 2 alloys, to help you make the best choice that fits your applications needs.

2618 Aluminum Alloy Forged Pistons

2618 forged pistons are a low silicon based material. They expand and contact much more than their 4032 siblings. In most cases these pistons are used in extreme racing applications like NASCAR and NHRA. 2618 Pistons require a greater piston to bore clearance due to their tendency to expand when heating up. This process can be heard during a cold start and is known as piston slap. The primary reason they are used in high performance applications is their forgiving nature under high impact situations such as detonation. However, their flexibility means you sacrifice longevity, as they distort much quicker than a 4032 forged aluminum piston. So, if you plan on putting a lot of stress on your HEMI and going to the strip often you may want to consider the benefits of a 2618 piston.

4032 Aluminum Alloy Forged Pistons

4032 forged pistons are a high silicon based material. This means that they expand much less than 2618 pistons. The tendency to expand less means that the piston can have a tighter piston to bore clearance. The tighter clearances create a quitter overall operation of the motor. 4032 is a very stable allow that resists distortions such as ring integrity. The alloy’s strength and stability also lends its self to a longer life cycle capability. However due to its less ductile nature we do not recommend using this type of piston if you’re planning to build your HEMI stroker motor for a boosted application. If you’re looking to build a naturally aspirated HEMI stroker engine and don’t plan on abusing the motor every weekend you should consider a 4032 piston for you build.