428 CJ/R & SCJ/R "Q" 4V
(R=Ram Air)
428 "Q" (1966-68)
428 "P" (1966-70)
(P=Police Interceptor engine)
Engine Type 8 cylinder
90 degree,
Overhead Valves (OHV)
8 cylinder
90 degree,
Overhead Valves (OHV)
Displacement 428 cu.inches (CID) 428 cu.inches (CID)
Maximum torque

440 lbs./ft. @ 5,400 RPM

362 lbs/ft. @ 2,800 RPM ("Q" series)

459 lbs./ft. @ 3,200 RPM ("P" series)

Maximum Horsepower 335 BHP @ 5,400 RPM 345 BHP @ 4,600 RPM ("Q" series)

340 BHP @ 5,400 RPM ("P" series)

Firing Order 1-5-4-2-6-3-7-8
(Number 1 cylinder on right bank, nearest radiator)
(Number 1 cylinder on right bank, nearest radiator)
Bore & Stroke 4.132" X 3.984"
(104.9 mm X 101.19 mm)
4.132" X 3.984"
(104.9 mm X 101.19 mm)
Compression Ratio 10.6:1 (1968-69)

11.01:1 (1970)

Oil Pressure (hot) 35 to 60 lbf/in2 35 to 60 lbf/in2
Mains 4-bolt 4-bolt

Holley 4150-C (4V)
automatic choke (1968-69)
manual choke (1970)

Autolite 4100 (4V-1966-67)

Autolite 4300 (4V-1968-70)

Holley 4160 (2x4V- 1967 Shelby GT 500)

Holley 4150 (4V -1968 Shelby GT 500)

automatic choke all

Size of Carburetor 735 cfm Holley
Fuel premium gas premium gas
Intake Manifold cast iron

aluminum (Shelby only)

cast iron (all after 12/1968 except Shelby)

aluminum ("P" thru 12/1968 & all Shelby GT 500)

Valve train hydraulic lifters hydraulic lifters
Intake 2.082"-2.097" 2.022"-2.037"
Exhaust 1.645"-1.660" 1.551"-1.556"
Distributor single point (1968-69 all, 1970 auto only)

dual point (1970 4 speed only)
vacuum advance all

single point
vacuum advance

dual point (mechanical advance 1967 Shelby only)

Spark Plugs Autolite BF-32 Autolite BF-32
Long Block Weight
in lbs.
610 (with cast iron intake) 560
Emission Controls Thermactor Thermactor (all 1968-70 & California)
RPM Rev Limiter 6,050-6,150 RPM (1970 4 speed only)
The 428 Cobra Jet, introduced April 1968, was a high torque, quiet, and inexpensively built engine. Not intended for true racing durability, it lacked the bottom end features of the side-oiler 427. The cross-bolted main bearing caps and oiling improvements were missing. The thin cylinder walls of the 427's 4.23" bore made normal assembly line production impossible. The smaller bore of the 428 was well within normal production line capabilities. The longer stroke (3.98 vs. 3.78 for the 427) gave the engine powerful low-end punch.
The 428 CJ and SCJ blocks have extra main bearing webbing and thicker main caps than the normal 390 or 428.

Connecting rods are similar to those used in the 390 GT, but CJ and Police Interceptor engines are fitted with 13/32" bolts.

Unlike other FE family engines, the 428 is externally balanced. Due to different piston and connecting rod weights, there are actually four different 428 crankshafts. One used for normal 428, the 428 Police Interceptor, and the 428 CJ before 12/26/69. After that date Ford offered one crankshaft for 428 CJ. Two were offered for 428 Super Cobra Jet before and after that date.
The 428 CJ cylinder heads featured an un-machined chamber of 73-76cc, 2.06" intake valves and 1.66" exhaust valves. The intake ports measured 1.34" x 2.34". Exhaust ports measured 1.28" x 1.84". The 16-bolt pattern exhaust face was unique to the CJ heads. A 735 cfm Holley carburetor sat on a cast iron intake manifold. Curiously, the 428 Police Interceptor received an aluminum intake. Dished pistons with valve relief's resulted in 10.6:1 compression. A thermactor air injection system was required to meet federal emissions standards. Special free flowing cast iron exhaust manifolds were fitted, similar to those used on 427 Galaxies. The Q-code CJ was rated at 335 BHP @ 5600 RPM, obviously under rated.

The Super Cobra Jet, available only with a 3.91 or 4.30 rear axle ratio, included additional features. For improved high speed reliability, the SCJ used the beefier LeMans style capscrew connecting rods and forged pistons. This heavier reciprocating assembly required additional balance mass on the crankshaft added via a special front oil seal sleeve with a cast-on counterweight. An engine oil cooler forced the horns to both be located on one side of the car. A reinforcement plate was used for the horn bolts behind the radiator core support -- often lost, or missing from fakes. Air conditioning was not available because the oil cooler used up the space in front of the radiator. The SCJ engines used 427 Le Mans style rods with capscrews and forged pistons.

Ram Air option was installed on R-code cars. A scoop was mounted on top of and part of the air cleaner assembly. A square hole cut in the hood allowed the scoop to come through the hood when closed. The alignment of the scoop in relation to the air cleaner and the opening in the hood was adjustable. The now
famous term "shaker hood scoop" is appropriate, especially when the engine has a more aggressive camshaft.
The 428 "P" engine was used in the 1966 AC Cobra The 1967 Shelby GT 500 and the 1968 Shelby GT 500 used "Q" engines.

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