Speedmaster PCE281.2168 Pontiac 400 455 215cc 72cc Ram Air IV Hydraulic Flat Assembled Cylinder Heads

Speedmaster Pontiac heads include valve sizes at 2.11" Intake, and 1.66" While the 2.11" valves are standard issue, the valve seat can be machined to accept a larger valve with minimal work. CNC Ported heads in this application will soon be available. Speedmaster CNC ported cylinder heads are machined on dedicated 4-axis and 5-axis CNC machining centers to ensure accuracy and cost effectiveness.On the CNC ported versions, combustion chamber, Exhaust and Intake Ports all fully CNC machined for better flow. CNC combustion chambers offer superior control over flame travel and quench area. CNC Ported heads eliminate human error and variation from port to port. Unsurpassed repeatability from one cylinder head to another that is commonly found in "Hand porting & Polishing" Combustion chambers are exact in volume - so every cylinder has the same compression ratio. Each port is the same cross section - so every cylinder can reach higher true RPM potential. CNC machining produces ports and chambers to within tolerances of no more than .002"; in turn every cylinder can reach the same power potential and accurate tuning. HEAD GASKETSThe head gasket we recommend for our Pontiac heads is Felpro #10171. (4.540 Bore) or Fel Pro#1016 (4.300 Bore) INTAKE GASKETSOur heads are manufactured with the Ram Air IV pattern which requires Felpro #1233 gaskets. PUSH RODSPlease measure for exact pushrod length once heads and rockers are fully installed. Deck machining, head gasket thickness and rocker arm style will all affect pushrod height.SPARK PLUGSAll Speedmaster Pontiac heads use standard 14mm. x 750" reach, 5/8 hex, gasket seat sparkplugs like NGK R5671A-7, Autolite 3924, Champion RC12YC, etc. Remember that higher compression/ boost require a colder heat range sparkplug.HEAD BOLTS / STUDSOur Pontiac heads utilize standard Ram Air Iv head bolts or studs.The ARP head bolt part number is 190-3605.EXHAUST GASKETSWe recommend the use of Edelbrock exhaust gaskets #7281 or any comparable item of your choice.