Cylinder head casting number usage

 1964-74 PONTIAC V8 CYLINDER HEAD CASTING NUMBERS1964 326/250 hp 326/280 hp 389/215, 230, 235 hp 389/267, 283, 303, 306 hp 389/325, 330, 348 hp 421/320 hp 421/350, 370 hp1965 326/250 hp 326/285 hp 389/256 hp 389/290, 325, 333 hp 389/335, 338, 360 hp 421/338 hp...