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I am getting ready to rebuild my 350 engine. I have a simple piston question for you all. What is the difference between HYPEREUTECTIC Pistons and FORGED Pistons? What are advantages that come with each?

Thanks for the help.

MT
 

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King of my Man-cave.
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Hypereutectic pistons are cast with a higher content of silicon that give them more strength than normal cast pistons. They are also harder and less prone to ring land pound-out and other detonation/preigntion damage. They have less thermal expansion and can be run quite tight (.001" piston-to-wall clearance).

Forged pistons are made with the aluminum forced under pressure into a mold. There are two main alloys, 2618 and VMS-75. 2618 is stronger but does not have any silicon so it does not have the scuff-resistance and has more thermal expansion that VMS-75. Thus, the 2618 is more suited to race only applictions while the VMS-75 is better suited to high-performance street, bracket-racing, etc. applications. 2618 pistons run more piston-to-wall clearance than do those made of VMS-75.

tom
 

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Discussion Starter #3
Tom,

Thank you very much for the info.

In your opinion, which piston is better? I am building a 350 for a 67' Camaro. I would like as much HP as possible but also the most torque i can get. I want to be able to drive it on the street and race it a little. I might even spray it with a little gas. I already have the top end of the motor. So i just need to build a strong bottom end.

Thank you again for any help you can give me.

Matthew
 

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Well, I ain't Tom but I think if you keep the juice to 150hp or less you'll be fine with hypereutectic pistons.

DO NOT use Keith Black pistons if you intend to use nitrous. The rings are too close to the crown. I don't care what the K-B website says. Otherwise they are fine pistons for a street engine.

Larry
 

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If you do use KB pistons, be sure & read the instructions relating to ring gap & also the extra ring gap required for nitrous use. KB's need a wider gap than standard pistons because of the above mentioned proximity of the top ring to the top of the piston. Nitrous increases the needed gap even more.
 
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