These Chevrolet Performance  CNC-ported LS3 cylinder heads flow more than 350 cfm at 0.600 in. lift (intake side) at 28 in. of water restriction, and to nearly 370cfm at higher valve lifts. They feature 276cc intake runners and 92cc exhaust ports, along with a combustion chamber volume of 68cc.The cylinder heads will fit any LS engine with cylinder bores of 4.000 in. or larger. The Chevrolet Performance Parts CNC-Ported LS3 cylinder heads are delivered fully assembled, with 2.165 in. hollow stem intake valves and 1.59 in. solid stem exhaust valves, as well as valve springs, valve locks, spring retainers, and valve stem seals.

NOTE: THE ZL1 SPEED SHOP HAS MADE 730HP AT 6800 RPM WITH THESE HEADS ON PUMP GAS 93 OCTANE. WE HAVE USED THESE HEADS ON AT LEAST 25 DIFFERENT ENGINES IN THE PAST FEW YEARS. IN OUR OPINION THIS IS THE BEST HEAD TO USE FOR NATURALLY ASPIRATED APPLICATIONS, OR APPLICATIONS WITH MINIMAL BOOST AND/OR NITROUS.  

* THESE HEADS AT CHECKOUT PRICE ARE ONLY GOOD TO .570 LIFT, BUT WE CAN CUSTOM BUILD THEM UP TO .760 LIFT FOR AN ADDITIONAL FEE.  CONTACT US FOR MORE INFORMATION.