" " "Number of exhaust valves per cylinder (usually 1, 2 for 4-valve) p 28" "Outside diameter of one exhaust valve in inches p 28" "Avg diameter of runner or header pipe (enter 'C' to calc) p 29" "Length of header pipe & port in inches from collector to valve p 29" "Port/valve flow efficiency (enter 'C' to calc from flow bench data) p 29" "Flow efficiency of header (enter 'C' to calc from flow bench data) p 30" "CFM flow of exh @1.5''Hg, Open Headers=100000 (enter 'C' to calc) p 30" " " "Enter 'Y' or press to accept values and return to MAIN MENU" " " " " " "