M311 LS3 Cylinder Heads

The Frankenstein M311 273cc LS3 Cylinder Heads represent a substantial upgrade over OEM heads, engineered to deliver horsepower far beyond stock capabilities. Each head is fully CNC ported with a 5-axis high-performance program, then meticulously hand-blended and deburred to ensure extreme attention to detail and precise tolerances, backed by strict quality control processes. These "Monster Series" heads feature a 68cc chamber volume, a 273cc intake port, a 112cc exhaust port, and an 11° valve angle. The exhaust ports are O-Ringed with hi-temp silicone o-rings included, and 2" headers are recommended for optimal performance. Built to order, these cylinder heads have an approximate lead time of 4-6 weeks for completion. Both the standard "Monster" and the "Boost Monster" versions are designed to fit all standard equipment, including valve covers, headers, LS3 intakes, and OEM-type LS3 rocker arms, though billet rocker stands are available separately.