1969 Mustang Engine Information & Specs - 250 Cubic Inch Inline 6

1969 Mustang Engine Information & Specs – 250 Thriftpower Six

250 Thriftpower Inline 6 Technical Specs & Data

1969 Mustang Engine Information – Thriftpower Inline 6 (250 cubic inch)

Introduced in 1969, the 155 horsepower 6 cylinder was needed because of the Mustang’s increase in size. The 200 cubic inch six although still offered was way underpowered to handle the new Mustang. However, in my opinion, to really power a Mustang always required an 8 cylinder engine and buying a 6 (or 4 cylinder in later years) was like buying 3/4 or 1/2 an engine. But you didn’t get a discount from the dealer for the part of the engine they forgot to install.

Engine Basics

Year 1969
Cylinders 6
Displacement 250 cu / 4.1 liters
Power (hp) 120 hp @ 4,400 RPM
Torque (lb/ft) 190 lb/ft @ 2,400 RPM
Compression 8.1:1
Bore x Stroke 3.682 x 3.910

Engine Specs (250 cid inline 6)

Spark Plugs
Oil filter
Gas Filter
Air Filter
PCV
Oil Pressure 35 – 55 PSI
Points Gap and Dwell at xxx RPM
Timing 6 Degrees BTDC Manual & 12 Degrees BTDC Automatic
Valve adjustment
Valve size
Valve arrangement E I E I E E I E I I E Front to rear
Manifold Vacuum 17 inches at idle
Warm Idle Manual Trans 575-600 RPM
Warm Idle Auto Trans 500-525 RPM
Carburetor CFM
Bore and stroke 3.500 X 2.940
Compression 9.1:1 (155 – 199 psi @ cranking speed)
HP and Torque 101 hp at 4400 RPM and 158 ft/lbs torque at 2400 RPM
Taxable HP 29.4
Distributor Rotation Counter-Clockwise
Firing order 1 – 5 – 3 – 6 – 2 – 4

Clutch information: for the 3 spd,  9″ diam.  6 Springs, Pressure plate orange cover, purple springs, aluminum stripe. Disc is 9″ diameter, 6 springs, Blue with blue springs.

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.

Head bolts 70-75
Main cap bolts 60-70
Rod end bolts 19-24
Intake bolts
Exhaust manifold bolts 13-18
Harmonic damper 85-100
A/C Compressor mounts
Engine fan
Motor mounts to engine
Bellhousing bolts
Trans to bellhousing
Flywheel to Crankshaft 75-85
Oil pan bolts
Valve cover bolts
Carburetor mount bolts
Oil pickup
Spark plugs
Trans. inspection plate
Water pump bolts

Crankshaft Bearing Journal Specifications

Main Bearing Journal (inches)

Journal Diameter 2.3982 – 2.3990
Oil Clearance 0.0005 – 0.0022
Shaft end play 0.004 – 0.008
Thrust on number 5

Connecting Rod Journals

Journal Diameter 2.1232 – 2.1240
Oil Clearance 0.008 – 0.0024
Side clearance 0.003 – 0.010

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 0.015 – 0.055

Piston Specifications

Code Red 3.6778 – 3.6784
Code Blue 3.6790 – 3.6796
0.003 Oversize 3.6802 – 3.6808
Piston to Cyl. Bore clearance 0.0014 – 0.0020
Piston Pin Bore Dia. 0.9122 – 0.9125

Valve Specifications

Year 1969
Seat angle 45
Face angle 44
Valve spring pressure lbs/inches [email protected]
Valve spring installed height (in) 1 19/32
Stem guide clearance (in) – Intake 0.0008 – 0.0025
Stem guide clearance (in) – Exhaust 0.0010- 0.0027
Stem Diameter (in) – Intake 0.3104
Stem Diameter (in) – Exhaust 0.3102
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