This Page Last Updated on: Saturday, September 23, 2006 11:14 PM



Piston Tolerances
Oil Ring Gap .030" +.020", -.005"
Pin Fit .0006" +-.0001" Slip Fit
Piston-to-Head Clearance .030" with Steel Rods, .040" with Aluminum Rods
Piston-to-Valve Clearance .100" minimum Intake .125" minimum Exhaust
Piston-to-Wall Nominal Clearance 1959-1965 389 Cast (.001") 1966-1967 389/400 Cast (.0025") 1968-1971 350/400 Cast (.0028") 1972-1976 350/400 Cast (.0033") 1977-1979 400 Cast (.0029") 1968-1970 Ram Air Forged (.0058") 1973-1974 Super Duty Forged (.0064")
Ring-to-Groove .0015" -.005"
Second Ring Gap .015" +.010", -.005"
Top Ring Gap 326/389 .021" +- .005" 350/400 .019" +- .010", -.005" 428/455 .021" +-.010", -.005"