Bare Aluminum Heads LS3 11 Degree Rectangular Port 260CC Runner 72cc Pair. This product data sheet is originally written in English. Pair of Bare Aluminum Heads LS3 11 Degree Rectangular Port 260CC Runner 72cc. 11 DEGREE LS3 Rectangular PORT 260CC INTAKE RUNNERS. 355-T6 HIGH DENSITY ALUMINUM MATERIAL. 500 OD BRONZE VALVE GUIDES. SPRING SEATS MACHINED TO 1.560. SPARL PLUG 3/4 REACH TAPERED SEAT. COMPATIBLE W/GM LSX BLOCKS. ACCEPTS GEN IV LS3 INTAKE MANIFOLD. Pair of Bare Aluminum Heads LS3 11 Degree Rectangular Port 260CC Runner 72cc 11 DEGREE LS3 Rectangular PORT 260CC INTAKE RUNNERS 355-T6 HIGH DENSITY ALUMINUM MATERIAL. 500 OD BRONZE VALVE GUIDES SPRING SEATS MACHINED TO 1.560″ SPARL PLUG 3/4″ REACH TAPERED SEAT COMPATIBLE W/GM LSX BLOCKS ACCEPTS GEN IV LS3 INTAKE MANIFOLD.