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Automotive Aftermarket Manufacturing

MAHLE Motorsport Introduces USRA Factory Stock PowerPak

Each USRA-approved piston kit includes a 1.5, 1.5, 3.0mm file fit performance ring set and heavy-duty steel wrist pins.


MAHLE Motorsport, a leader in USA made high performance race pistons and rings, announces a Small Block Chevy 23° USRA Factory Stock PowerPak Piston Kit designed to meet all USRA Factory Stock rules. A PowerPak kit is available for 357, 359, 361 and 362 cubic inch engines. Each USRA approved piston kit includes a 1.5, 1.5, 3.0mm file fit performance ring set and heavy-duty steel wrist pins as seen in this video.


United States Racing Association (USRA) rules only allow for a stock appearing engine inclusive of standard weight cast or forged (minimum 4 grams) four (4) equal valve relief flat top or dished pistons. The rules permit standard weight wrist pins (minimum 130 grams) and minimum 1.5mm, 1.5mm, 3mm piston rings. A maximum six one-hundredths (0.06) inch oversized ring is permitted. 

MAHLE’s new 23° SBC forged pistons for USRA Factory Stock are manufactured from high strength 4032 aluminum alloy and have a four equal valve relief design. The pistons are forged in a slipper skirt design that is both lightweight and stable, preferable for racing applications.  Each piston has precision CNC machined pin bores with straight side reliefs in the pin bores for more accessible wrist pin lubrication. 


Machined to exacting tolerances, with ultra-flat ring grooves for maximum sealing, MAHLE’s PowerPak kits designed for grassroots and Sportsman racing applications provide extra value both in their design and coatings. Each PowerPak kit features MAHLE’s GRAFAL® skirt coating to reduce drag between the piston skirt and cylinder bore, reduce wear on the bore and skirt fatigue.  MAHLE also goes the extra step by applying a Phosphate dry lubricant coating to fight friction and transfer heat out of the engine quicker. By lowering the piston’s operating temperature there is less opportunity for pin galling and microwelding, especially at startup. 


For more information about MAHLE Motorsport USRA SBC PowerPak sets including clearances, compression height, pin diameter, and part numbers, visit



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