High-Performance Piston Set for Twin Cam Harleys - +.010" Oversize - Boost Engine Power & Durability for Cruising and Racing

Spawned from this successful manufacturer's line of automotive pistons. Lightweight permanent mold cast pistons. Manufactured from Hypereutectic 390 Alloy, contain 16-18% silicon, and heat treated to T6 specifications producing a stronger than stock piston. Special alloy compositon keeps heat confined to the combustion chamber and reduces heat transfer to the piston itself producing a cooler running piston. Can be fitted with a clearance as small as .00075". Piston expansion is reduced by as much as 20% over conventional pistons. Less piston rock, better ring support, more durability and better retained compression for maximum power. The key feature to these pistons is the accumulator groove between the top and second ring which averages the normal pressure between the first and second ring, keeping the pressure low enough to prevent lifting of the top ring while maintaining preload on the second (oil scraping) ring. Each set of pistons includes wrist pins, spiral locks, engine assembly lube, and Hastings Moly rings. Wrist pins measure .792" O.D. on single cam models and .927" O.D. on Twin Cam models.