Foxbody Mustang Ignition & Fuel System

The factory DuraSpark I and DuraSpark II ignition systems used on the late model Foxbody Mustang was actually an excellent ignition system for the time. Read below for all the information you need regarding the ignition and fuel system on Foxbody Mustangs. HO firing order, ignition timing, spark plug gap, fuel pump and injector specifications, it's all below.

Ford 5.0 V8 Cylinder Location
Ford V8 Firing Order
Foxbody Mustang Spark Plugs
Foxbody Mustang Fuel Pumps
Ford Fuel Injector specifications
1979-1985 Foxbody Mustang Ignition Timing
1986-1993 Foxbody Mustang Ignition Timing


1979-1993 Ford V8 Cylinder Banks (facing engine head on)

Left Bank | Right Bank
4 | 8
3 | 7
2 | 6
1 | 5

1979-1993 Ford V8 Firing Order
1979-93 truck V8's (non-HO) and 4.2 L V8: 1-5-4-2-6-3-7-8
1982-93 5.0 L HO V8: 1-3-7-2-6-5-4-8

Foxbody 5.0L Firing Order

1979-1993 V8 Foxbody Mustang Spark Plugs
Year Engine Part Number Gap
1979 5.0 L
5.0 L (California)
ASF-52
ASF-52-6
0.050 in
0.060 in
1980 4.2 L ASF-42 0.050 in
1981 4.2 L ASF-42 0.050 in
1982 4.2 L ASF-52 0.050 in
1983-85 5.0 L 4bbl
5.0 L CFI
ASF-42
ASF-52
0.044 in
0.050 in
1986 5.0 L HO AWSF-52/44 0.050 in
1987-93 5.0 L HO ASF-42 0.054 in
1993 GT40 Cobra AWSF-42C 0.050 in

1979-1993 V8 Foxbody Mustang Fuel Pumps (factory)
Carburated Mustang (mechanical fuel pump): 1979:6.5 psi, 1982:8.5 psi
CFI Mustang: twin electric: 60 lph @ 39 psi
SEFI Mustang: 88 lph @ 39 psi

Ford Factory Fuel Injector Specifications

Flow Color Factory Application Injector Power Capacity
14 lb/hr Grey Non Mustang 5.0 L V8's (trucks, not HO) Don't bother. Change them
19 lb/hr Yellow 5.0 L HO V8 Mustang 330 HP
24 lb/hr Light blue Cobra GT40 (93-95) 400 HP
30 lb/hr Red 2.3 L turbo (early models) 500 HP
35 lb/hr Brown or dark blue 2.3 L turbo SVO Mustang 600 HP

1979-1985 Foxbody Mustang V8 Ignition Timing

Year Initial Timing (deg BTC) Centrifugal Advance (deg @ rpm) Vaccuum Advance (deg @ in. Hg)
1979-81 12 0.0 @ 1250rpm
8.0 @ 2150rpm
14.5 @ 5000rpm
0.00 @ 3.5
14.0 @ 8.0
24.0 @ 13
1982 12 0.0 @ 1200rpm
10.0 @ 2000rpm
19.0 @ 5000rpm
0.00 @ 3.5
14.0 @ 8.0
24.0 @ 13
1983 10 0.0 @ 1400rpm
9.0 @ 2000rpm
18.0 @ 5000rpm
0.00 @ 4.5
11.0 @ 8.0
20.0 @ 12.5
1984 10 0.0 @ 1400rpm
11.0 @ 2200rpm
20.0 @ 5000rpm
0.00 @ 4.5
10.5 @ 8.0
20.0 @ 12.5
1985 12 0.0 @ 1300rpm
11.0 @ 2200rpm
20.0 @ 5000rpm
0.00 @ 4.5
11.5 @ 8.0
20.0 @ 12.5

1986-1993 Foxbody Mustang V8 Ignition Timing
Simply add the amount of your initial timing to any point along the curve and you'll have the total timing for that point. For example if your running an A9L computer and 15 degrees initial timing and you want to know how much total timing you have at 2600 rpm. You would simply add the 15 initial to the 22.5 shown on the chart for a total of 37.5 degrees.

ECU 1000 rpm 1800 rpm 2600 rpm 3500 rpm 5000+ rpm
A9L 8 ° 18.5 ° 22.5 ° 22 ° 26 °
A9P 21.25 ° 21.25 ° 27.25 ° 26 ° 30.75 °
X3Z (Cobra) 8 ° 18.5 ° 22.5 ° 22 ° 25 °