4.050; 3.500 Stroke; 5.700 Rod; 4-Valve Flat Top; PRESS-FIT Pin
The POWERPAK kit is the racer’s best value. Developed for high performance enthusiasts and engine builders who want uncompromising reliability, the POWERPAK delivers just that.
The forged piston kits are made from either 4032 aluminum alloy, which allows for tighter cylinder-to-wall clearances and improved temperature stability, or 2618 alloy, which adds strength and increased detonation resistance.
In addition to fully machined crowns and CNC machined pin bores, the pistons are dual coated with phosphate to reduce micro-welding and pin galling, and the skirt features a GRAFAL anti-friction coating. Each set includes low-drag rings proven to increase horsepower and torque, and application-specific pins—all designed to ensure minimum friction and maximum horsepower.
| Part No. | Cubic Inches | Bore | Stroke | Rod | Comp Height | Pin Diam. | Crown Vol | Wght G | Compression Ratio | Alloy | Clearance Guide | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 58cc | 64cc | 70cc | Meas. | Min | Max | ||||||||||
| 930203830 | 357 | 4.030 | 3.500 | 5.700 | 1.560 | 0.927 | -3.0cc | 475 | 11.6 | 10.7 | 10.0 | 4032 | 0.500 | 0.0036 | 0.0044 |
| 930203840 | 359 | 4.040 | 479 | 11.6 | 10.8 | 10.0 | |||||||||
| 930203850 | 361 | 4.050 | 483 | 11.6 | 10.8 | 10.1 | |||||||||
| 930203860 | 362 | 4.060 | 487 | 11.7 | 10.8 | 10.1 | |||||||||
| 930203880 | 366 | 4.080 | 495 | 11.8 | 10.9 | 10.2 | |||||||||
SBC 23° USRA Factory Stock Rules Forged Piston - PRESS-FIT Pin
1.5, 1.5, 3.0mm File Fit Performance Ring Set Included
Meas.: The location to measure piston-to-wall clearance, referenced from the bottom of the piston skirt.
Min and Max: the suggested range of clearance over the coating for each application.
Compression Ratio: calculated at zero deck and 0.040” gasket unless otherwise noted.
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