1970 Mustang Engine Information – 302 cubic inch V-8 (4.9 L Windsor V8 + & Boss V8)
The 302 Windsor + The Boss 302
The 302 cubic inch engine was introduced in 1968 to the Mustang and continued to be offered in 1970 although it was largely overshadowed by the newer more powerful engines. The Boss 302 engine continued to be offered in 1970 also.
Technically, all 302 engines with the exception of the Tunnel Port and the Boss have 2 bolt mains. The main difference between 1969 and 1970 was on the distributor side of the equation, the Boss utilized a dual point, vacuum advance distributor with RPM limits of 6,050-6,150 in 1970. The street 302’s and the Tunnel Port used a single point vacuum advance distributor.
Learn more about the Ford Mustang 302 engine
Engine Basics
| Year |
1970 |
1970 Boss |
| bbl |
2 barrel |
4 barrel |
| Cylinders |
8 |
8 |
| Power (hp) |
210 hp @ 4,400 RPM |
290 hp @ 5,800 RPM |
| Torque (lb/ft) |
295 lb/ft @ 2,400 RPM |
290 lb/ft @ 4,300 RPM |
| Compression |
9.5:1 |
10.5:1 |
| Displacement |
302 cu / 4.9 liters |
302 cu / 4.9 liters |
| Bore x Stroke |
4.000 x 3.00 |
4.000 x 3.00 |
Engine Specs (302 cid V8)
| Spark Plugs |
|
| Oil filter |
|
| Gas Filter |
|
| Air Filter |
|
| PCV |
|
| Oil |
5 quarts of 10W30 or 10W40 |
| Oil Pressure |
35 – 60 PSI |
| Points |
Gap and Dwell at xxx RPM |
| Timing |
6 Degrees BTDC Manual & 6 Degrees BTDC Automatic |
| Valve adjustment |
|
| Valve size |
|
| Valve arrangement |
R. Side I E I E I E I E Front to rear |
| Valve arrangement |
L. Side E I E I E I E I Front to rear |
| Boss 302 Valve Adj. |
Mechanical Hot lifter adjustment for the Boss 302- 0.025 Intake and Exhaust |
| Manifold Vacuum |
18 inches at idle |
|
|
| Warm Idle Manual Trans |
575-600 RPM |
| Warm Idle Auto Trans |
475-500 RPM |
| Carburetor CFM |
|
| Bore and stroke |
4.00 X 3.0028 |
| Compression |
9.5:1 (155 – 199 psi @ cranking speed), 9.0:1 5.0L |
| Compression Pressure |
130-170 @ cranking speed |
| HP and Torque |
210 or 225 (HO) hp at 4400 RPM and 158 ft/lbs torque at 2400 RPM |
| Taxable HP |
51.2 |
| Distributor Rotation |
Counter Clockwise |
| Firing order |
Non H.O.’s = 1 – 5 – 4 – 2 – 6 – 3 – 7 – 8 |
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 |
65-70 |
| Crank cap bolts |
60-70 |
| Rod end caps |
19-24 |
| Intake bolts |
20-22 |
| Exhaust manifold bolts |
15-20 |
| Upper intake on EFI |
12-18 |
| Harmonic damper |
70-90 |
| A/C Compressor mounts |
|
| Engine fan |
|
| Motor mounts to engine |
85 |
| Bellhousing bolts |
|
| Trans to bellhousing |
25 |
| Flywheel to Crankshaft |
75-85 |
| Oil pan bolts |
7-9 |
| Valve cover bolts |
10 |
| Carburetor mount bolts |
|
| Oil pickup |
10-15 |
| Spark plugs |
|
| Oil pump mounting bolts |
22-32 |
| Trans. inspection plate |
|
| Water pump bolts |
15-22 |
| Clutch Pressure plate |
35 |
| Water Pump |
20 |
| Upper cam gear bolt |
40-45 |
| Rocker arm bolts |
18-25 |
| Camshaft thrust plate |
10 |
Crankshaft Bearing Journal Specifications (302)
Main Bearing Journal (inches)
| Journal Diameter |
2.2482 – 2.2490 |
| Oil Clearance |
0.0005- 0.0024 Except #1 bearing which is 0.001- 0.0018
|
| Shaft end play |
0.004 – 0.008 |
| Thrust on number |
3 |
Connecting Rod Journals
| Journal Diameter |
2.1228 – 2.1236 |
| Oil Clearance |
0.008 – 0.0026 |
| Side clearance |
0.003 – 0.010 |
Crankshaft Bearing Journal Specifications (302 Boss)
Main Bearing Journal (inches)
| Journal Diameter |
2.2482 – 2.2490 |
| Oil Clearance |
0.0005- 0.0024 Except #1 bearing which is 0.001- 0.0018
|
| Shaft end play |
0.004 – 0.008 |
| Thrust on number |
3 |
Connecting Rod Journals
| Journal Diameter |
2.1222 – 2.1230 |
| Oil Clearance |
0.0015 – 0.0025 |
| Side clearance |
0.003 – 0.010 |
Piston Ring Specifications (302)
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 – 0.069 |
Piston Ring Specifications (302 Boss)
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 – 0.069 |
Piston Specifications
|
302 |
302 Boss |
| Code Red |
3.9984 – 3.3990 |
3.9968 – 3.9974 |
| Code Blue |
3.9996 – 4.0002 |
3.9980 – 3.9986 |
| 0.003 Oversize |
4.0008 – 4.0014 |
3.9992 – 3.9998 |
| Piston to Cyl. Bore clearance |
0.0018 – 0.0026 |
0.0034 – 0.0042 |
| Piston Pin Bore Dia. |
0.9123 – 0.9126 |
0.9122 – 0.9125 |
Valve Specifications
| Year |
1970 |
1970 Boss |
| Seat angle |
45 |
45 |
| Face angle |
44 |
44 |
| Valve spring pressure lbs/inches |
180 @ 1.23 |
315 @ 1.31 |
| Valve spring installed height (in) |
1 21/32 |
1 13/16 |
| Stem guide clearance (in) – Intake |
0.0010 – 0.0027 |
0.0010 – 0.0027 |
| Stem guide clearance (in) – Exhaust |
0.0015 – 0.0032 |
0.0015 – 0.0032 |
| Stem Diameter (in) – Intake |
0.342 |
0.342 |
| Stem Diameter (in) – Exhaust |
0.3415 |
0.3415 |
Tune Up Specs
| Year |
1970 “F” Code |
1970 Boss |
| Spark Plug |
Autolite BF-42 |
Autolite AF-32 |
| Plug Gap |
.032″-.036″ |
.035″ |
| Dwell |
24-29 (manual), 26-31 (automatic) |
30-33 |
| Point Gap |
.017″-.021″ |
.020″ both sets |
| Intake |
1.773″-1.788″ |
2.225″ -2.375″ |
| Exhaust |
1.442″-1.457″ |
|
| Carburetor |
Autolite 2300-A (2V) Automatic choke |
Holley 4150-C (4V), manual choke
|
