Swap Meet Guide To SmallBlock Chevy Cylinder Head ID
Dec 12, 2018 · SmallBlock Chevy GenI Cylinder Heads. Standard GenI smallblock Chevy heads position the valves at a 23degree angle to the deck. In 1989, Chevy introduced the 18degree Bow Tie aluminum head that shifted the valveangle vertically, while simultaneously raising the intake port to take advantage of this angle.