Ignition Timing

Determine specified timing and mark degree line on damper (some vehicles mark both pointer and damper notch). Disconnect vacuum line(s) at distributor and plug lines.
For vehicles with dual mode timing ignition module, disconnect the 3-pin switch assembly connector from the ignition module.
NOTE: Vehicles built in 1979 may be equipped with dual mode timing modules. They may be identified by having an ignition barometric pressure switch assembly (located near the ignition module) and include 3 connectors.
Connect tachometer to engine. Connect a timing light to No. 1 spark plug wire. Reset timing, if timing is more than ±2° from specification.
Recheck timing. Reconnect 3-pin connector to dual mode timing ignition module and check function of barometric pressure switch. Compare basic timing to requirements for elevation at which test is conducted:

ELEVATION-TIMING RELATIONSHIP

Elevation Above Sea Level	Basic Timing
Below 2400 ft.	Specification less 3-6°
2400-4300 ft.	Specification or Specification less 3-6°
Over 4300 ft.	Specification

NOTE: If timing cannot be set, check for presence of roll pin retaining reluctor to sleeve in distributor shaft. Verify Orange and Purple wires are not reversed between distributor pickup coil and ignition module. This will cause timing to be 22 1/2 degrees off.

1975 IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

Application

Man. Trans.

Auto. Trans.

302"

⁽¹⁾

351W"

.....

12° @ 650

351M"

.....

12° @ 650

360

6°@650

⁽¹⁾

390

.....

6°@650

400

12° @ 650

460

14° @ 650

⁽¹⁾	See Emission Control Tune-Up Decal under hood.

1976 IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

Application

Man. Trans.

Auto. Trans.

302"

⁽¹⁾

351W

12° @ 650

351M

12° @ 650

360

6°@650

⁽¹⁾

390

6°@650

400

12° @ 650

460

14° @ 650

⁽¹⁾	See Emission Control Tune-Up Decal under hood.

1977 IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

Application

Man. Trans.

Auto. Trans.

302"

F100

Federal & Calif.

6° @ 550

High Alt

8° @ 550

10° @ 550

U100 (Bronco)

⁽¹⁾ 8° @ 550

8° @ 550

351" W

Light Duty

Federal

8° @ 800

⁽²⁾ 14° @ 800

Calif.

14° @ 500

High Alt.

12° @ 550

12° @ 500

Heavy Duty

Federal

6° @ 650

8° @ 550

Calif.

6°@650

⁽³⁾8° @650

351" M

Light Duty

Federal

10° @ 500

⁽⁴⁾ 10° @ 500

Calif.

18° @ 500

High Alt.

10° @ 500

Heavy Duty

Federal

⁽⁵⁾12°@650

⁽⁶⁾ 12°@ 850

Calif.

10° @ 650

400"

Light Duty

6° @ 500

Heavy Duty

Federal

12° @ 650

Calif.

12° @ 650

⁽⁷⁾10° @ 650

460"

12° @ 650

⁽¹⁾	4° @ 550 with Calibration No. 7-53H-R10.

⁽²⁾	12° @ 550 with Calibration No. 7-65A-R0, 14° @ 500 with Calibration No. 7-65U-R0.

⁽³⁾	6° @ 650 with Calibration No. 7-76J-R10.

⁽⁴⁾	6° @ 500 with Calibration No. 7-60G-R11.

⁽⁵⁾	6° @ 650 with Calibration No. 7-71-R10.

⁽⁶⁾	14° @ 650 with Calibration No. 7-72-R10.

⁽⁷⁾	12° @ 650 with Calibration No. 7-74J-R0.

1978 IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

Application				Man. Trans.	Auto. Trans.
302"
	Federal			6°@550	8°@550
	Calif.			6°@550	10° @ 550
	High Alt.			12° @ 550	10° @ 550
351" W
	Light Duty
		E100
			Federal	8°@600	14° @ 500
			Calif.	.....	10° @ 500
			High Alt.	.....	12° @ 550
		E150/250		4°@500	8°@500
	Heavy Duty
		Federal		6°@650	8°@550
		Calif.		.....	6°@650
351" M
	Light Duty
			Federal	8°@500	10° @ 500
			Calif.	6°@500	8°@500
			High Alt.	.....	14° @ 500
	Heavy Duty			6°@650	14° @ 650
400"
	Light Duty
			Federal	12° @ 650	12° @ 650
			Calif.	.....	10° @ 650
460"
			Federal	.....	12° @ 650
			Calif.	.....	14° @ 650

1979 IGNITION TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

Application

Man. Trans.

Auto. Trans.

302"

Light Duty

Federal

⁽¹⁾ 6° @ 550

⁽²⁾6°@ 550

Calif.

⁽³⁾6° @ 550

351" M Engine

Light Duty

Federal

10° @ 650

6° @ 550

Calif.

⁽⁴⁾10°@650

⁽⁵⁾ 6° @ 500

Heavy Duty⁽⁶⁾

6° @ 600

12° @ 600

351" W Engine

Light Duty

Federal

4° @ 500

⁽⁷⁾10° @ 500

Calif.

8°@500

Heavy Duty⁽⁶⁾

6° @ 650

400" Engine

Light Duty

Federal

10° @ 650

6° @ 550

Calif.

.....

6°@500

Heavy Duty

3° @ 600

460" Engine

Light Duty

All Models

.....

14° @ 650

Heavy Duty

All Models

.....

8°@650

⁽¹⁾	4° @ 550 for Calibration No. 9-53H-R0 Federal Man. Trans.

⁽²⁾	8° @ 550 for Calibration No. 9-54H-R0 Federal Auto. Trans.

⁽³⁾	8° @ 550 for Calibration No. 9-54S-R0 Calif. Auto. Trans.

⁽⁴⁾	8° @ 650 for Calibration No. 9-59S-R0 Calif. Man. Trans.

⁽⁵⁾	10° @ 500 for Calibration No. 9-60S-R0 Calif. Auto. Trans.

⁽⁶⁾	Without catalytic converter.

⁽⁷⁾	12° @ 500 for Calibration No. 9-64H-R0 Federal Auto. Trans.

NOTE: To improve performance on 1975-76 Federal Bronco and Pickups with 302", 360" and 390" engines, the timing may be advanced up to 6° over base specification. Test drive vehicle and ensure detonation does not occur.

NOTE: Some 1977 pickups may exhibit spark knock. To correct this, the timing may be retarded up to 6° until the knocking goes away.

NOTE: On engines that idle smoothly but become rough at 1000-2000 RPM, check for crossed Orange and Purple primary ignition wires between distributor and module. To check, turn ignition key off and set engine at initial timing mark firing point. One spoke of distributor armature should be opposite stator pole. If pole is between spokes or offset, primary wires are probably crossed.