Feed Your Big-Bore LS Lots of Air with AFR LS3 270cc Cylinder Heads

The bigger the cylinders your engine has, the more air you can pack into it. It’s science.

If you have an LS engine with 4.000-inch or larger cylinder bores, a pair of AFR LS3 270cc Cylinder Heads can feed it plenty of power-building air. At .600-inch of valve lift, the heads flow 376 cfm of air on the intake side and 238 cfm on the exhaust. At .700-inch of valve lift, we’re talking 389 cfm intake/245 cfm exhaust. That makes the AFR heads ideal for high-RPM power production and engines running large amounts of boost or nitrous oxide.

The rectangular port aluminum heads have 12-degree valve angles that increase piston-to-valve clearance and allow the use of higher-lift camshafts. The large 2.20-inch intake valves allow better cylinder filling and intake charge efficiency. That means the heads can support strong mid-range and sustained top-end power.

Specifications:
• CNC-ported 270cc intake and 93cc exhaust runners
• CNC-ported 69cc combustion chambers with five-angle competition valve job
• 2.20-inch intake and 1.57-inch exhaust valves
• 1.27-inch Pacaloy dual valve springs for hydraulic roller cams rated up to .650-inch valve lift
• Bronze valve guides, 7-degree steel valve locks and 7-degree titanium retainers
• 6-bolt pattern for better head-gasket stability under elevated cylinder pressures

AFR LS3 270cc Cylinder Heads fit aftermarket and LSX blocks with a 6-bolt head bolt pattern. They are sold in pairs.

CHECK OUT AFR’S LS3 270CC CYLINDER HEADS