ATK HPBBC315 BBC 120cc/315cc Cylinder Heads Assembled (Each)

Description

Specifications:
Material A356 Aluminum
Intake Port Volume 315cc Rectangle Port
Intake Port Dimension 2.450″H x 1.755″W
Intake Port Location Stock
Intake Valve Size 2.25”
Intake Valve Material Stainless Steel
Exhaust Port Volume 124cc
Exhaust Port Dimension 1.780″H x 2.031″ W
Exhaust Port Location .375″ Raised
Exhaust Valve Size 1.88”
Exhaust Valve Material Stainless Steel
Combustion Chamber Size (As Cast) 120cc
Valve Cover Bolt Pattern Perimeter Bolt
Valve Angle Stock
Valve Spring Pocket Diameter 1.728″ O.D
Valve Spring Dual w/ Dampener
Valve Spring Setup Height 2.000”
Valve Spring Closed Pressure 160lbs (W/Retainer)
Valve Spring Open Pressure 1.400” .600” Lift 400lbs / 1.350” .650” Lift 425lbs (W/Retainer)
Valve Spring Max Lift .675”
Valve Guide Material Manganese Bronze
Valve Seal Material Viton
Valve Seat Material Powder Metal
Retainer Material Steel with 10° Locks
Deck Thickness .750″
Minimum Bore Diameter 4.250″
Flat Mill .006” per cc
Spark Plug Dimensions 14mm x .708″ with Gasket Seat
Torque Specifications Per Application Based on Factory or Aftermarket Bolts/Studs

Recommended Components:
Intake Port Gasket Fel Pro 1275-5
Exhaust Port Gasket Per Application
Head Gasket Factory Block Fel Pro 508SD or 1017-1
Head Bolts ARP 135-3607
Head Studs ARP 235-4103
Spark Plug Starting Range Autolite 3923 as starting point
Lifters Per Application
Pushrods 3/8 Pushrods are recommended (must check length)
Rocker Arms We suggest an aftermarket full roller based on application

Disclaimer: It’s up to the installer to verify all fitment and components will work on the engine. Everything listed is just a recommendation. ATK is not responsible for damage to heads or engines due to miss matched components or wrong application.

These cylinder heads are Flow Tested on a Super Flow SF600 bench with a 4.030” bore size @28” water. Clay intake radius was used, Flow tube was not used on the exhaust port.

Int.       Exh.

Lift       0.100”    104        101
Lift       0.200”    165        140
Lift       0.300”    237        190
Lift       0.400”    305       237
Lift       0.500”    321        256
Lift       0.600”    368       270
Lift       0.700”    379        282
Lift       0.800”    387        293