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. The Aeroflow Performance small block Chevy cylinder heads are designed for street/race performance engines to give the ultimate in flow at a competitive price. Made from A356 aluminium castings, these 220cc cylinder heads are ideal for operating in the idle to 7500 rpm range. These bare cylinder heads will fit a 4.00" bore and larger. Aeroflow cylinder heads are sold as pairs.