420+c.i., high compression, high RPM, rectangular CNC-ported heads in race type applications.
Fits 4.8, 5.3, 5.7, 6.0, 6.2 and 7.0 Liter LS1, LS2, LS3, LS4, LS6, LS7 plus SUV and Truck Engines (Grinds are specific to displacement and cylinder head design)
