The Aeroflow Series of Aluminium Cylinder Heads are taking affordable performance street and strip cylinder heads to the next level. These heads utilise ultra-smooth A356-T6 aluminium castings, new as-cast runner and chamber designs produce excellent flow numbers. This combined with a 5-angle competition valve job, diamond-honed bronze guides, hand bowl blending and professional assembly help to outperform some of the best brands in the business. Aeroflow's Big Block Chrysler cylinder heads are designed for entry-level street performance engines and ideal for operating in the idle to 6500 rpm range. Made from A356 aluminium castings. These complete heads include larger-than-stock 1.55" (39.4 mm) diameter dual valve spring to handle up to 0.600" (15.24mm) maximum valve lift. Recommended spark plugs are 14mm x 3/4" reach with flat gasket seat. Includes valves, valve springs, retainers & locks.Head Specs: Chamber Volume: 84cc Chamber Intake port volume: 210cc Intake valve size: 2.14"Exhaust valve size: 1.81"Valve spring diameter: 1.55" (39.4mm)Spring installed height: 1.73" @ 140lbsMaximum valve lift: 0.600" (15.24mm) @ 310lbsPushrod diameter: 3/8"Spark plug style: Straight Flow Chart cfm @ H2O .100" .200" .300" .400" .500" .600" 2.14 Intake 80 144 209 257 279 294 1.81 Exhaust 72 126 161 189 206 219