The Aeroflow Performance small block Ford Windsor cylinder heads are designed for street / race performance engines to give the ultimate in flow at a budget price. Made from A356 aluminium castings with fully CNC’d ports and combustion chambers. The 185cc cylinder heads are ideal for operating in the idle to 6500 rpm range. The complete heads include larger then stock 1.32" (33.5mm) diameter dual valve spring to handle up to 0.600" (15.25mm) maximum lift. Suits flat tappet and hydraulic camshaft. Complete heads include valves, valve springs, retainers & locks, guide plates and 7/16" rocker studs. Sold as a pair.