Ford 427 428 429 Specs

Ford Big Block Engine Specifications

Part Cobra Jet Super Cobra Jet Additional Notes
Optional and Mandatory Parts
Location of Horns One on left & one on the right Two horns on the right side The engine oil cooler was placed on the left side resulting in both horns being placed on the right side
Air Conditioning Optional Not offered
Axles 31 spline gear 31 spline gear Also offered on the Boss 302 and Boss 429 Mustangs
Traction Lok Axle Optional Standard feature when car was ordered with 3.91 axle
Detroit Locker Rear Not offered Standard feature when
car was ordered with a
4.30 axle
Engine Oil Cooler Not offered Mandatory Option Found on the left side at the horn location resulting in both horns being placed on the right side.
Ram Air Optional Optional Ram air was an option on either
Cobra Jet and Super Cobra Jet motor
Staggered Rear Shocks only on the 4 speed cars only on the 4 speed cars
Automatic Transmission Optional Optional The Ford C6 automatic Transmission was available with either motor.
Extra Shock Tower Bracing Mandatory Option Mandatory Option Also offered on Boss 302 and
390 GT Mustangs

Parts Unique to the Cobra Jet Mustangs

Part Unique to the Cobra Jet? Unique to the Super Cobra Jet? Additional Notes
Pistons Yes Yes The Cobra Jet Pistons were Cast. The Super Cobra Jet's were forged.
Crankshaft Yes Yes
Connecting Rods Yes Yes The Cobra Jet had 428 connecting rods upgraded with 13/32" rod bolts. The Super Cobra Jet connecting rods were 427 LeMans rods with a cap screw bolts.
Fly Wheel & Flex plate Yes Yes The balances were different
Balancer & Damper Yes Yes The balances were different
Crankshaft Spacer Yes Yes The Cobra Jet used the 390 Spacer. The Super Cobra Jet used a special unique spacer
Cylinder Heads No No Both engines used the same cylinder heads
Engine Block No No Both engines used the same engine block
Engine Oil Pan No No Both engines used the same oil pan
Distributor No No Both engines used the same single point distributor. A dual point distributor was not a Ford factory installed part.
Intake Manifold No No Both engines used the same cast iron intake manifold
Distributor No No
Hydraulic Camshaft No No Both engines used the same hydraulic camshaft
Automatic Transmission (C6) No No Both featured a cast iron tailshaft on the Ford C6
Manual Transmission No No Both featured a mandatory big input shaft and close ratios gears
Carburetor No No Both engines used the same Holley 735 CFM carb
Exhaust Manifold No No Both engines used the same cast iron header type exhaust manifolds

Casting or Tag Numbers

Crankshaft Ford part number 1UB or A Ford part number 1UA or B (requires a unique balancer cast C9ZE-6A300-A The Cobra Jet crank shaft is also found in the 428-4V motor, the 428 Police Interceptor and Mercury 410 engines
Connecting Rods Ford part number C6AE-C, C6AE-F or
Ford part number C6AE-E or C9ZE-A The Cobra Jet had 428 connecting rods upgraded with 13/32" rod bolts. The Super Cobra Jet connecting rods were 427 LeMans rods with a cap screw bolts
Fly Wheel Ford part number C8OE-A Ford part number C9ZE-A
Flex Plate Ford part number C6VP-B or C7AP-A Ford part number
Balancer & Damper Ford part number C8AE-6316-A (7"
Ford part number C8AE-6316-C (7.5" diameter)
Crankshaft Spacer
Cylinder Heads

Ford part number C8OE-6090-N

16 exhaust manifold bolts per cylinder head
Engine Block
Engine Oil Pan
Intake Manifold

Ford part number C8OE-9425-C

Often the 428 Police intake in was used in place of the cast iron CJ/SCJ intake since the Police Interceptor used an aluminum intake.
C6 Automatic Transmission
Ford part number
C8OF-12127-J (68-69)
DOZF-12127-G (1970)
The Ford C6 Automatic with a cast iron tailshaft
4 Speed Transmission
Ford part number
C8OF-12127-H (68-69)
DOZF-12127-C (1970)
All cars had Ford's close ratio 4 Speed
Hydraulic Camshaft

Ford part number

There is a blue paint mark in front of 3rd cam journal
Automatic Transmission (C6)

Tag# PGB-AF1 or

Torque converter


12" 1,830-2,030 stall
Manual Transmission Tag# RUG-AE2 or
Located on the transmission case
Bellhousing Ford part numbers
Before 2-15-68 C6OA-B or C6OA-D
After 2-15-68 C8OA-6394-D
Cluth fork

Ford part number


Ford part numbers
C9AF-N for auto transmission
Ford part number
C9AF-M for manual transmission

Holley 735 CFM
Carburetor spacer

Ford part number

Fuel pump

4441 X

Carter Model
Exhaust Manifold Left Side Ford part numbers
Before 9-2-68
C8OE-9431-A or H.
After 9-2-68
Exhaust Manifold Right Side Ford part numbers
Before 9-2-68
C8OE-9430-A or B.
After 9-2-68

If you wanted a big block engine in 1968 you could choose a 427, 428 or the new 429. The top performance motor was the 427. The 428 was a ten year old FE design, more tamed down. And the new 429 was a brand new design called the "385" series. Available in two versions in 1968, the 429 and the huger 460. The later motor was for Lincolns and Mercury's.

The 429 was unique in many ways. It offered:

  • Thin wall casting
  • Longer bore centers than the FE block
  • Huge bearings
  • Canted-valve cylinder heads forming a slightly hemi-spherical combustion chamber
  • Rocker shafts were replaced with rockers riding on fulcrums with separate pedestals

The canted-valve design angled the valves in the head. This allowed for larger ports and valves. It also permitted an better unshrouded mixture of gasoline and air into the chamber.

Ford needed a better NASCAR and NHRA motor. The 427 was gone. So Ford engineers developed a unique set of heads and placed them on a 429 Mustang in 1969. This Mustang was called the Boss 429. The head design was also used on a special 302 Mustang. That car was named the Boss 302. Ford sold enough Boss 429 Mustangs to qualify the motor for racing. The aluminum heads used in the Boss 429 engines featured:

  • Modified hemi-spherical design
  • One long and one short rocker arm per cylinder
  • A single camshaft
  • Stronger main bearings
  • Different oiling system
  • Four bolt mains

The Boss 429 was a "385" motor but with the above changes is not interchangeable with other 429 blocks.

In 1970 the 428 Cobra Jet Motor was replaced with a 429 CJ engine. The change occurred in the middle of the production year so some early Cobra Jet cars had 428's, later cars were 429's. The 429 Cobra Jet package included:

  • Bigger heads with larger ports and valves
  • Stamped steel rocker arms
  • Screw-in rocker studs in the early 70 models
  • Guide plates like used in the Boss 302's
  • Compression was increased from 10.5:1 to 11.3:1
  • Cast iron intake manifold
  • Single 700 cfm Rochester carb
  • Rated at 370 horse power

In 1971, Ford offered the Super Cobra Jet 429. This upgrade offered:

  • Four bolt mains
  • Forged aluminum pistons
  • Bigger oil pump
  • External oil cooler
  • Cast iron crank shaft with higher nodularity than the base 429
  • Mechanical camshaft with adjustable rocker arms
  • Single 780 cfm Holley carb

The 429 motor was phased out in 1973. It's sister motor, the 460, continued in production.

The 460 motor is a 429 with longer stroke, same bore. In 1968, when it was first offered, the 460 was rated at 360 horse power with 10.5:1 compression. By 1972 the compression dropped to 8.5:1 with a horse power rating decrease to 212 HP. The next year, 1973, saw the compression down to 8.0:1 and horse power at 200 HP. However the way horse power was stated changed during this time. Early motors were rated using flywheel or brake horsepower, in '72 net horsepower was used. (The difference being whether all the power robbing accessories are considered.)

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.

EXP 133, 134, 474, 503

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