Technical Specifications of...
Merlin III Cylinder Heads

Material: 355-T6 high density aluminum alloy
Valve Seats: Steel intake, hardened steel exhaust
Valve Guides: Bronze
Valve Spring Seats: Machined for 1.640" springs
Valve Size: 2.300" x 1.880"
Rocker Arm Studs: 7/16" screw-in style with hex shoulder. Furnished with assembly
Exhaust Flange: Stock port location and accessory bolt holes
Included In Base Assembly: Manley forged stainless steel valves with swirl-polished heads, umbrella-style (-2 models) or PC style (-3 & -4 models) valve seals, 1.550" ( -2 & -3 models) or 1.625" (-4 model) Hardcore valve springs, Manley 7° chrome moly (-2 models), 10° chrome moly (-3 models) retainers and keepers. -4 models have 10° titanium retainers.
Recommended Installation Items:
Head Gaskets: Fel-Pro #1017-1 or equivalent
Pushrods: Requires heat-treated pushrods
Spark Plugs: Accepts 14mm .750" reach, gasketed. Accel 416 or equivalent. Heat range may vary. Consult with engine builder.
Intake Gasket: Fel-Pro #1211, Mr. Gasket 121 or equivalent
Exhaust Gasket: Fel-Pro #1410 or equivalent
Head Bolts: 10 longer than stock required (World #832015-10)