3V Performance CNC ported LS3 11* 6 bolt head

3VL Aluminum Cylinder Head, 5 axis cnc ported, LS 6 bolt Block Chevy, 270cc Intake Runner, 68-72cc Combustion Chamber,11° Rectangular Port, Steel Retainers ,Assembled 375 cfm intake cfm tested on S/F 1020 bench ( add 15-20cfm for S/F 600 ) 11° valve angle Solid, stainless 2.165” intake / 1.595” exhaust valves 4.000” minimum bore size 3VPM-1436 DUAL SPRING KIT - .650-.690" LIFT Spring specs: •170 lbs @ 1.780" •160 lbs @ 1.800" •145 lbs @ 1.850" •415 lbs @ 1.112 •Coil bind @ 1.060"