This is a genuine 1971 LT1 4 bolt main block from a 1971 Z-28 Camaro with a 4 speed. The original CGP suffix code still clearly visible. Date codes indicates a manufacture date of July 29, 1970 and assembly date of August 3, 1970. The block is currently .040 over with no sleeves. The main bearing caps fit snugly in the saddles. This is very solid, rebuildable core, perfect for a numbers matching restoration.