Fits 302/351 Windsor engines Cast from prime A356 T6 aluminum Heads are cast with high-flow ports 20 degree inline valves Premium stainless steel 2.02" intake M-6507-A304 and 1.60" M-6505-B304 exhaust valves Uses M-6513-BH conical style valve springs with machined retainers and machined valve locks. Most hydraulic cams can be used with these springs. 130# @ 1.800", 318lbs. @ 1.200" and CB @ 1.150" Includes laser cut guide plates M-6566-Z304D for use with 5/16" pushrods and 7/16" rocker studs Steel alloy intake and exhaust valve seats Manganese-bronze valve guides 63cc CNC'd combustion chamber Intake port volume as cast: 204cc Exhaust port volume as cast: 85cc Accepts both tapered seat and gasket style 14mm spark plugs (Motorcraft AGSP-32-PP, Autolite 3924, 3925) Requires M-6564-F351 1.65:1 or M-6564-G351C 1.5:1 ratio roller rocker arms with .150" offset intake pushrod cup (not included) Raised exhaust port exit, custom headers may be required Ford Racing M-9439-A50 intake manifold gasket recommended Uses Felpro® exhaust gasket part number 1487 Felpro® VS13264T valve cover gasket recommended Check piston to valve clearance including radial valve clearance before installing these cylinder heads on your engine