1969 Mustang Engine Information – 428 cubic inch V-8 (7.0 L Boss V8)
429 Boss V8
The Boss 429 engine was offered late in 1969 and was rated at over 370 horsepower. It had aluminum heads with extremely large free flowing ports, contoured exhaust manifolds, a high rise intake manifold to help it gain horses.
The block was a strengthened 429 cast block. They had HP429 cast into the front left side of the block. The 4 bold main engine had forged crank and connecting rods. The first 279 (model (820-S) engines used NASCAR type connecting rods, the remainder of the engines (model 82-T) used beefed up production type rods.
The aluminum heads used oversized valves set at an angle to each other placing the exhaust valves closer to the exhaust manifold and the intake valves directly in line with the intake manifold thus the breath- ability of the engine was maximized. This “crescent” design was similar to the hemi design used in other engines. There were no head gaskets use when assembling the 429. “O” rings were used to seal all water and oil passages as well as the individual cylinders.
An aluminum intake manifold was mated with a 735 cfm Holley carburetor. Valve covers were either magnesium or aluminum depending on date of production.
Engine Basics
Year |
1969 |
bbl |
4 |
Cylinders |
8 |
Displacement |
429 cu / 7.0 liters |
Power (hp) |
375 hp @ 5,200 RPM |
Torque (lb/ft) |
450 lb/ft @ 3,400 RPM |
Compression |
10.5:1 |
Bore x Stroke |
4.360 x 3.590 |
Engine Torque Specifications
All torque specifications provided in this table are those recommended by FORD. If you use special bolts, follow the torque specifications provided by the manufacturer. I recommend that you use the 3 step torque technique where you torque down the bolts in three equal steps. Once you have reached the maximum recommended torque setting, go around one more time. Do not torque in a circular pattern. Always torque cross to cross.
|
429 BOSS |
Head bolts |
90-95 |
Main cap bolts |
70-80 |
Rod end caps |
85-90 |
Intake bolts |
25-30 |
Exhaust manifold bolts |
28-33 |
Harmonic damper |
70-90 |
A/C Compressor mounts |
|
Engine fan |
|
Motor mounts to engine |
|
Bellhousing bolts |
|
Trans to bellhousing |
|
Flywheel to Crankshaft |
75-85 |
Oil pan bolts |
12 |
Valve cover bolts |
10 |
Carburetor mount bolts |
|
Oil pump |
|
Spark plugs |
|
Trans. inspection plate |
|
Water pump bolts |
|
Clutch pressure plate |
|
Water pump |
20 |
Upper cam gear |
|
Rocker arms |
|
Main cap cross bolts |
|
Crankshaft Bearing Journal Specifications (Boss 429)
Main Bearing Journal (inches)
Journal Diameter |
2.2994 – 3.0002 |
Oil Clearance |
0.0010 – 0.0025 |
Shaft end play |
0.004 – 0.008 |
Thrust on number |
3 |
Connecting Rod Journals
Journal Diameter |
2.4992 – 2.500 |
Oil Clearance |
0.008 – 0.0025 |
Side clearance |
0.010 – 0.020 |
Piston Ring Specifications
Comp Ring Width
Top |
0.077 – 0.078 |
Bottom |
0.077 – 0.078 |
Ring side clearance
Top |
0.002 – 0.004 |
Bottom |
0.002 – 0.004 |
Oil ring |
Snug |
Ring gap width
Top |
0.010 – 0.020 |
Bottom |
0.010 – 0.020 |
Oil Ring |
0.010 – 0.035 |
Piston Specifications (429 SCJ and BOSS)
Code Red |
4.3569 – 4.3575 |
Code Blue |
4.3581 – 4.3587 |
0.003 Oversize |
4.3593 – 4.3599 |
Piston to Cyl. Bore clearance |
0.0030 – 0.0038 |
Piston Pin Bore Dia. |
1.0402 – 1.0405 |
Valve Specifications
Year |
1969 |
Seat angle |
Intake 30, Exhaust 45 |
Face angle |
Intake 29, Exhaust 44 |
Valve spring pressure lbs/inches |
315 @ 1.31 |
Valve spring installed height (in) |
1 13/16 |
Stem guide clearance (in) – Intake |
0.0010 – 0.0024 |
Stem guide clearance (in) – Exhaust |
0.0020 – 0.0034 |
Stem Diameter (in) – Intake |
0.3715 |
Stem Diameter (in) – Exhaust |
0.3705 |