New COMP Cams Nostalgia Plus ZL-1 mechanical flat tappet camshaft for Big Block Chevrolet engines. This camshaft has an intake duration of 262 and exhaust duration of 272 at .050 lift. The valve lift is .581 on the intake and .622 on the exhaust with a 110.0 lobe separation. It is still in the original protective plastic wrap and box.