• Designed for any new Gen IV short-block with 4.000" bore or larger
• The 6-Bolt design is compatible with GM LSX and World LSX blocks
• Accepts Gen IV LS3 valvetrain and intake manifolds.
• Uses a 2.165" intake valve and 1.600" exhaust valve
• Has a 256cc intake port
• Has a 69cc combustion chamber standard
• Has a deck thickness of .750"

Each Mast Black Label cylinder head assembly includes:

• A fully CNC machined Mast Black Label aluminum cylinder head
• Mast micro finished .650 lift beehive valve springs
• Mast lightweight stainless steel intake & exhaust valves
• Mast lightweight steel retainers
• Mast machined locks

NOTE: Gaskets, valve covers, rocker arms and pushrods not included

Flow Data w/4.070" Bore Plate
Lift Intake Exhaust
0.100 77 56
0.200 148 118
0.300 237 165
0.400 295 208
0.500 328 227
0.600 351 235
0.700 370 241