Comparison of Major 428 Engine Components

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This summary comparison of major 428 engine components was prepared by Bill Barr, Principal Engineer for the 428 Cobra Jet engine development program at Ford Motor Company. Unless specifically noted this comparison does not include the parts that are unique to the 428 Super Cobra Jet engine.

ComponentTasca KR-8
(estimated)
428 Police Interceptor428 Cobra Jet
Cylinder HeadsC3AE-6049-HC7AE-6049-D
(Production 390 - 410 - 428 - 428 PI)
C8OE-6049-N
Similar to earlier C4AE-H but with enlarged intake and exhaust ports, valve seat throat clearance cutter, and improved water jacket core print
Intake ManifoldAluminum PIAluminum PICast iron, similar to PI with revised carburetor bore risers, relocated carburetor pad, and radiused riser to upper and lower logs to improve fuel/air distribution
Exhaust ManifoldsExhaust headersProduction 390 GT cast iron light car manifoldsRedesigned high flow, low restriction unique to the 428 CJ
Air CleanerUnknownLight car 390 GTRedesigned dual inlet with hot/cold start-up system. Upgrade available to low restriction ram air (seal to hood) and "shaker" hood with hot/cold start-up system
Thermactor Secondary Air SystemNoneAir inlet to exhaust manifoldsAir inlet to exhaust ports
Carburetor635 or 650 CFM Holley
1.6875" x 1.6875" primary and secondary bores
Ford P&E 600 CFM 4V

Holley 735 CFM 4V (780 CFM modified with FT (Ford Truck) booster nozzles for improved atomization and emissions)

1.75" x 1.75" primary and secondary bores

CrankshaftProduction 428 PIProduction 428 PIProduction 428 PI
(Note that Bill's original notes used for this page said "Special 50% nodularity for improved strength", but we can't find any evidence that suggests that the original CJ crank was anything other than the same crank used with the 428 PI)
Connecting RodsProduction 428 PIProduction 428 PILarger bolts; SCJ had material added to outside of big end
Crankshaft Mass BalanceProduction 428 PIProduction 428 PIRebalanced special crankshaft
Crankshaft DamperProduction 428 PIProduction 428 PIRetuned damper for strengthened crankshaft
Camshaft390 GT390 GT390 GT
Valve Springs and Valve Toss SpeedProduction 428 PI
(6000 RPM)
Production 428 PI
(6000 RPM)
Revised valve springs for higher valve toss speed (6700 RPM)
Intake ValvesRegular ProductionProduction 428 PIImproved material with modified, polished backside fillet radius
Exhaust ValvesRegular ProductionProduction 428 PIImproved material with modified, polished backside fillet radius
Oil Filter AdapterProduction 428 PIProduction 428 PIUnique adapter with oil in and oil out provisions for external oil cooler (SCJ only)
Flywheel and ClutchProduction 428 PIProduction 428 PIUnique high (90%+) nodular iron with 10,000 RPM burst strength; high RPM clutch assembly
Oil Pump and Oil PressureProduction 428 PIProduction 428 PIHigher relief valve pressure, unique oil filter adapter, and external oil cooling (SCJ only)
TransmissionAutomatic onlyAutomatic and manual transmission availableAutomatic and manual transmission available. Upgraded C6 with higher shift speed and modified clutch packs
Exhaust SystemUnknownStandard 390 GT MustangNew 6" HG with miminal exhaust restriction mufflers and pipes
Rear Shock Absorber MountsProduction 1967 MustangProduction 1967 - 1968 MustangRevised for staggered shock absorbers to eliminate reverse gear tramping
Power OutputUnknown≈ 295 "B" Curve HP and 395 ft-lb Torque≈ 340 "B" Curve HP/420 ft-lb Torque

The engine engineering personnel who worked for me on the 428 program were Paul Lampela, Frank Gondoly, Bob Snider, and Matt Hecht.