Rear Axle Ratio; Oxygen Sensors; Exhaust Headers; Steering Components - Factory Five Racing Mk4 Roadster Assembly Manual

Rear Axle Ratio

From 1986 to 2004 8.8" rear axles were used in Mustangs. In 1994 they went from a 4.25" 4-lug bolt
pattern to a 4.5" 5-lug bolt pattern. Most wheels fit the 59.25" width the best. Make sure you know
what axle you have before ordering wheels.
Year Rear End Width
87-93
94-98
99-04

Oxygen Sensors

Oxygen sensors are placed in the exhaust to measure the oxygen content of the exhaust. From 1986-
1995, Ford Mustangs used two oxygen sensors, one in each side of the exhaust system. From 1996-
2004, Mustangs used four oxygen sensors, two per side. At full throttle the oxygen sensor signals are
not used by the computer, because the computer has a built in program to run the engine rich at wide
open throttle. Oxygen sensors will usually be most effective when placed near the collection point of
headers because the exhaust will remain very hot, and an average measurement of all of the cylinders
can be taken. All oxygen sensors are recommended to be used when placing a fuel injected engine into
a Factory Five kit.

Exhaust headers

1986 to 1993 Mustang headers have 1.5" tubes, and remained the same shape. From 1994 to 1995
Mustang headers still have 1.5" headers, but the collector flanges have a larger ball and socket joint.
1996 to 2004 Mustangs used cast exhaust manifolds. SOHC engines had circular exhaust ports, and the
DOHC had oval ports; however the collector flange changed in 2003 and 2004. Factory Five Produces
J-pipes to connect stock Mustang headers in a reversed position to Roadster 4 port side pipes for the
following years: 1986-1995, 1996-2004. 4 into 4 headers are also available from Factory Five for the
following applications: pre 1995 289/302, 96-04 SOHC 4.6L, 96-04 DOHC 4.6L, 351W, 390/427/428
big blocks, and 429/460 big blocks. For those installing 351 Windsor engines there are a few companies
that carry exhaust headers for the installation of a 351 Windsor into a 1986-1993 Mustang. These
headers will work with Factory Five 1986-1995 J-pipes.

Steering components

Power steering racks from 1987 - 2004 are mostly all 15:1. In 1994 the racks switched from having a
splined shaft for attachment to the steering column to a triangle shaped end, as well as changing the
inner and outer tie rod ends. The 1994 to 2004 inner and outer tie rods are too long and do not work
Manual
2004 3.55
2003 3.55
1996-2002 3.27
1995 3.08
1994 3.08
1987-1993 2.73
Rear Brake Type
59.25" 9" drum
61.125" 10.5" solid disc (GT)
62.52" 10.5" solid disc (GT)
www.factoryfive.com
Optional Automatic
2.49
3.27
3.27
3.27
3.27
3.08 3.27
11.65" vented disc (Cobra)
11.65" vented disc (Cobra)
549
508-291-3443