Engine › COOL HEAD DOME STANDARD BORE 18CC COOL HEAD DOME STANDARD BORE 18CC $0.00 Sold Out CNC machined from billet aluminumInterchangeable O-Ringed domes allow you to adjust compression for fuel quality, elevation, timing or performanceSubstantial increases in cooling efficiency Sold Out Added! CNC machined from billet aluminumInterchangeable O-Ringed domes allow you to adjust compression for fuel quality, elevation, timing or performanceSubstantial increases in cooling efficiency