These pistons are specially designed for forced induction and nitrous applications. Pistons include .310" pocket depths and precision CNC machined ring grooves that accept 1/16, 1/16, 3/16 rings.

Includes:

• Pin #927-2950-15-51S (140g)
• Contact reduction grooves
• Double Spiro Locks # 927-042-CS
• Double Pin Oilers

Specs:

• Part #: J170817
• CID: 383
• Bore: 4.030
• Stroke: 3.750
• Rod Length: 6.000
• Block Height: 9.000
• Compression Height: 1.125
• Compression Ratio with 58cc chamber volume: 9.3
• Compression Ratio with 64cc chamber volume: 8.8
• Compression Ratio with 76cc chamber volume: 8.2
• Dome Volume: -28.0cc
• Gram Weight: 430
• Footnote: Oil Rail Support is Included
• Oversize: 0.030
• Recommended Ring Set (Check Proseal listing to determine oil ring tension): J10008-4030-5

Factory GM heads are used to define standard valve spacing and angle (thus 23°) for many small block Chevy Additionally most 23° aftermarket cylinder heads incorporate what is commonly known as "60/40 Shift" (See diagram at right) in order to allow for larger valves. All JE flat top and inverted dome shelf piston set designs accommodate "60/40 Shift" and will work with most aftermarket 23° cylinder heads, including those with oversized valves and angle milled surfaces. TFS "Twisted Wedge", AFR227 and Brodix 10X cylinder heads will require custom pistons.

With over 60 years of experience, JE Pistons is the leader in high performance forged pistons. We've built a reputation that the competition can only follow. JE has a history of manufacturing the highest quality pistons and components that professional engine builders, race teams, and high performance enthusiasts trust and rely on.

The top engine builders in NASCAR, ALMS, NHRA, AMA Supercross and others choose JE Pistons over any other brand. For over 60 years, JE's position at the forefront of performance piston manufacturing has been a result of continuous research and development of unique materials, piston designs and technologies. Utilising State-Of-The-Art CNC machines for manufacturing along with purpose-designed forgings, JE is able to maintain exacting specifications on each and every piston and hold tolerances to millionths of an inch. Also available from JE is industry-leading processes like Ultra Crown, a Digital Three Dimensional piston crown machining process and Finite Element Analysis (FEA). FEA is a computer process whereby stress and fatigue are tested on a computer model before it goes into production. JE is the only performance piston manufacturer to earn the QS-9000 quality standard which confirms that JE provides customers the highest standards in quality control. In addition, we also have State-Of-The-Art inspection equipment and testing equipment which enables us to constantly bring you, the customer, the very latest in piston design configurations.