390-427-428 Ford FE PERFORMER RPM Direct bolt-on for 61-76 390-427-428 Ford V8's. Complete heads include stainless steel 2.09'' intake and 1.66'' exhaust valves to clear the 4.050'' bores on a 390ci engines. These 428 Cobra Jet-sized valves promote excellent flow for streetable power, and the large valve seat inserts can be machined to accept 427 Ford Medium Riser valves (2.19''/1.73'') if desired. Rocker shaft mounting holes and exhaust bolt holes are heli-coiled for strength. Use head bolt kit #350-8557.