Matching pair of genuine GM rectangle port cylinder heads for Mark IV big block engines. Casting number: 14096188 (service replacement for 1970 LS6 heads). 118cc open chambers, 2.19″ inlet/1.88″ exhaust, hardened exhaust seats. Matched pair, both with cast date J289. Complete with push rod guides and studs. They appear to be completely unmolested and there is no visible damage, cracks or porting. I’ve had them in storage for years. These are Chevrolet’s best ever cast iron heads for high performance Gen IV big blocks -the real deal. GM aluminium dual plane intake also available.