1968 Mustang Engine Information – 302 cubic inch V-8 (4.9 L Windsor V8)
The “Economical” V8 Comes to Mustang
The 302 cubic inch engine was introduced in 1968 to the Mustang, one of seven variations of V-8s were available in the ’69–’73 models. It was designed with Federal emissions regulations in mind. Although it is a derivative of the 289 mustang, some parts are not interchangeable. In fact the block of a 289 cannot be used without some machining. Since the 302 crankshaft is larger, it requires a notched out section in the engine sidewall to allow the connecting rod end bolts to pass. If you are unsure of the parts you are using to build an engine, check tolerances carefully.
Both the engines are 90 degree V8’s. Both are built well and will run forever if you treat them right. I have put well over 500,000 miles on a 302 with minor problems and good maintenance. I have also owned a 1965, 1966 and 1967, 289 CID engine. They all pull strong and have lasted. Good maintenance as with everything is the key.
All 302 engines with the exception of the Tunnel Port and the Boss have 2 bolt mains. The Tunnel port has 4 bolt mains and the 302 Boss has 4 bolt mains and is cross bolted as well. All 302’s drank regular gas except the Tunnel port and Boss engines, they gulped premium gas. Of all the 302 engines, only the Boss had solid adjustable lifters all others had hydraulic lifters.
On the distributor side of the equation, the Boss utilized a dual point, vacuum advance distributor with RPM limits of 5,950-6,050 in 1969 and 6,050-6,150 in 1970. The street 302’s and the Tunnel Port used a single point vacuum advance distributor.
The “J Code” Upgrade
For 1968 only, a special high-performance version of the 302 was offered for the Shelby GT350. The main features included: an angled, high-rise aluminum or iron intake manifold, a larger Holley four-barrel carburetor, and bigger valves of 1.78 in (45 mm) intake and 1.6 in (41 mm) exhaust. It had a longer-duration camshaft, still with hydraulic lifters. The heads had special close-tolerance pushrod holes to guide the pushrods without rail rocker arms or stamped steel guide plates. The combustion chambers also featured a smaller quench design for a higher compression ratio and enhanced flow characteristics. Additionally, high-flow cast exhaust manifolds similar to those on the 289 Hi-Po K-code engine further improved output. Heavy-duty connecting rods with high-strength bolts and a nodular iron crankshaft were also included in this package. Rated power was estimated at 306 hp.
Learn more about the Ford Mustang 302 engine
Engine Basics
Year |
1968 “F” Code |
bbl |
4 barrel |
Cylinders |
8 |
Power (hp) |
|
Torque (lb/ft) |
300 lb/ft @ 2,600 RPM |
Compression |
9.0:1 |
Displacement |
302 cu / 4.9 liters |
Bore x Stroke |
4.00 x 3.00 |
Year |
1968 “J” Code |
bbl |
4 barrel |
Cylinders |
8 |
Power (hp) |
|
Torque (lb/ft) |
310 lb/ft @ 2,800 RPM |
Compression |
10.1:1 |
Displacement |
302 cu / 4.9 liters |
Bore x Stroke |
4.00 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
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 |
0.010 – 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 |
0.015 – 0.069 |
Piston Specifications
Code Red |
3.9984 – 3.3990 |
Code Blue |
3.9996 – 4.0002 |
0.003 Oversize |
4.0008 – 4.0014 |
Piston to Cyl. Bore clearance |
0.0018 – 0.0026 |
Piston Pin Bore Dia. |
0.9123 – 0.9126 |
Valve Specifications
Year |
1968 |
Seat angle |
45 |
Face angle |
44 |
Valve spring pressure lbs/inches |
180 @ 1.23 |
Valve spring installed height (in) |
1 21/32 |
Stem guide clearance (in) – Intake |
0.0010 – 0.0027 |
Stem guide clearance (in) – Exhaust |
0.0015 – 0.0032 |
Stem Diameter (in) – Intake |
0.3420 |
Stem Diameter (in) – Exhaust |
0.3415 |
Tune Up Specs
Year |
Spark Plug |
Plug Gap |
Dwell |
Point Gap |
Intake |
Exhaust |
Carburetor |
1968 “J” Code |
Autolite BF-42 |
.032″-.036″ |
26 – 31 for IMCO, 24 – 29 for Thermactor |
.017″ for IMCO, .021″ for Themactor |
1.773″ – 1.788″ |
1.442″ – 1.457″ |
Autolite 4300 (4V) Automatic choke |
1968 Tnl Port |
Autolite BF-42 |
|
|
|
2.01″ |
1.53″ |
Autolite 4300-A(2x4V) Auto choke, Holley 4160 (2x4V) manual choke |
no 302 was ever cross bolted you can only cross bolt a main cap if its a skirted block as the FE and modular motors