Upgrading your 1979-93 Mustang valve springs keeps your valves opening and closing properly when using more agressive cams. These performance kits from Trick Flow are lighter than stock springs and fit Foxbody OEM style cast iron heads. Included in each kit are the springs, seals, locks, shims, and gauges needed for installation. Choose from upgrade kits for OE style cast iron heads and Twisted Wedge Trick Flow heads. These spring kits fit 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, and 1993 Fox Body Mustangs.