Here it is! The BBC Fully CNC Ported FLOTEK “Jackal” 375 cc! Our BIGGEST and MOST POWERFUL out of the box BBC to date. This head is the track dominator! The FLOTEK “Jackal” 375 cc with 435 CFM is just wicked! Designed with the racer in mind, featuring a 127 combustion chamber. The ALL-NEW, Exceptional Steel Cast with a beautiful Polycrystalline Diamond Cut Finish and cast from a permanent steel mold makes the FLOTEK Cylinder Head an easy choice! Unbeatable design, superb performance and exceptional pricing accomplish everything for the marine or strip enthusiast! The FLOTEK “Jackal” works well with a 540 and 576 cubic inch motors.

The BBC CNC FLOTEK “Jackal” 375 CNC head is a great choice for out of the box horse power. The FLOTEK “Jackal” 375 CNC Cylinder head has a thick Deck Design and High Capacity water jackets that makes them a reliable choice for racing applications.

Accepts stock pistons, has raised valve cover rails and exhaust port location is raised .360”.


SOLID ROLLER (Part# 375-5058) – PAC1224 Up to .850 Lift CL 275# @ 2.00 OP 810# @ 1.150 C/BIND 1.100 O.D 1.62” Dual I.D. 0.85

SOLID ROLLER (Part# 375-5059) – PAC1248 Up to .950 Lift CL 332# @ 2.100 OP 950# @ 1.200 C/BIND 1.130 O.D 1.64” TRIPLE I.D. 0.63


  • Headers will bolt on in most applications. Some may have interference.
  • Recommendations: Hooker Super Comp Headers
  • Stock Bolt Spread
  • May be necessary to use lowered motor mounts


Specifications, Features & Optional Supporting Components

Head Bolt Torque75 Ft Lbs w/ oil
Rocker Stud Torque50 Ft Lbs w/ oil
Intake Port GasketFel Pro 1252-3 (320) Fel Pro 1211 (360)
Exhaust Port GasketFel Pro 1404
Head GasketFel Pro 1017-1
Head Bolts & StudsARP 135-3703 (12pt) 135-3606 (6pt) 235-4303 (Stud)
Stud GirdleHarland Sharpe G1114 (7/16)
Suggested ManifoldVictor Jr, Super Victor
Spark Plug Starting Range14mm (.750) Accel #416
Intake Port Volume375 cc
Exhaust Port Volume133 cc
Intake Valve Diameter (in)2.35 in
Exhaust Valve Diameter (in)1.88 in
Intake Valve Angle24/4
Exhaust Valve Angle15/4
Valve Guide MaterialBronze
Valve Seat Machine Style3-Angle
Combustion Chambers127cc
Max Spring Pocket Diameter1.625” O.D.
Rocker Arm Nut Thread Size7/16-20 in
Valve Cover Mounting StylePerimeter Bolt
Accessory Bolt Holes DrilledYes
Long Intake Runner373cc
Short Intake Runner367cc
Exhaust Runner133cc

Basic Package Components:
Intake Valve Hydraulic2.35 +.250
Exhaust Valve Hydraulic1.880 Stock Length
Intake Valve Solid2.35 +.250
Exhaust Valve Solid1.880 +.100
RetainersHardened Chrome Moly
Guide PlatesDART 2700123-4/PC-4247
Rocker StudMust have Clearance for Valve Spring Retainers
Valve SealsViton Positive Seals
Spring CupHardened Steel Cups
Valve Seat MaterialPowdered Metal
Valve GuidesManganese Bronze
Valve Locks7 Degree and 10 Degree

Part Specification

Flo-Tek Cylinder HeadID#Part Number
BBC 375 Bare850134007525375-500
BBC 375 Solid Roller PAC 1224 Assembled850134007549375-5058
BBC 375 Solid Roller PAC 1248 Assembled850134007594375-5059

Flow Chart


Dimensions & Weight

Big Block Chevy Bare31 Pounds
Big Block Chevy Assembled39.6 Pounds

Additional information

Weight 39.6 lbs
Dimensions 24.5 × 10.5 × 9 in

BBC 375 Bare (375-500), BBC 375 Solid Roller PAC 1224 Assembled (375-5058), BBC 375 Solid Roller PAC 1248 Assembled (375-5059)