Steering Box Ratios (from Dan Jones, m203253@ws2200.mdc.com)
------------------------------------------------------------
Here's the info I promised on steering box codes. The chart was taken
from the March 1993 issue of Mustang & Fords ("Steering Steady").
I've also included some of my steering notes that may be of interest.
Cheers,
Dan Jones
Ford Steering Box Codes
-----------------------
Long Shaft Boxes (HCC & HCA Prefix):
Application Tag Code Type Ratio Turns
----------- -------- ---- ----- -----
65-66 Mustang HCC AW Power 16:1 3 3/4
HCC AX Manual 16:1 3 3/4 *
HCC AT Manual 19.9:1 4 5/8
65-66 Comet and Fairlane HCA BZ Power 16:1 3 3/4
HCA CA Manual 22:1 6
65-66 Falcon HCA BY Power 16:1 3 3/4
HCA CA Manual 22:1 6
Short Shaft Boxes (SMA & SMB Prefix):
Application Tag Code Type Ratio Turns
----------- -------- ---- ----- -----
67-68 Montego and Fairlane SMAB Power 16:1 3 3/4
SMAC Manual 22:1 6
67-68 Falcon SMAF Manual 16:1 3 3/4
67 Mustang SMBA Manual 19.9:1 4 5/8
67-68 Mustang SMBB Manual 16:1 3 3/4 *
67 Mustang SMBC Manual 19.9:1 4 5/8
67-70 Mustang and Cougar SMBD Manual 19.9:1 4 5/8
67 Mustang and Cougar SMBE Manual 16:1 3 3/4 *
68 Mustang and Cougar SMBF Manual 16:1 3 3/4 *
69-70 Mustang and Cougar SMBF Manual 16:1 3 3/4
68-70 Mustang and Cougar SMBK Power 16:1 3 3/4
SMBK Manual 16:1 3 3/4 *
Notes:
-----
- * indicates special high performance applications such as GT, Boss,
Mach 1, etc.
- The steering boxes are identified by a tag attached to one of the
steering box cover bolts. Use the number of turns to verify ratio.
- Early (64-70) Mustang power steering is of the non-integral, add-on assist
type with a separate power cylinder and control valve. There is no
difference between the manual and power steering boxes, except for ratios.
The fast ratio manual steering box is the same as the power steering box.
- 1964-1970 Mustangs have two basic ratios:
1. 19.9:1 ratio, 4 5/8 turns lock-to-lock, used on all low performance
manual steering cars.
2. 16:1 ratio, 3 3/4, used on all cars with power steering and on manual
steering high performance cars (Shelbys, Bosses, GTs, Mach 1s, etc),
optional?
- 1964-1970 Mustangs have two shaft styles:
1. 1964 to early 1967 boxes are the long shaft style where the box and
steering shaft form one unit. There is no coupler, the shaft is one
piece from the box to the steering wheel.
2. Late 1967 through 1970 are the short shaft style. There is a couple
between the box and the steering shaft. This change was made to meet
Federal Motor Vehicle Safety Standards (FMVSS) which required a
collapsible steering column. Sector shafts were either 1" or 1 1/8".
There are four different '67-'70 short worms used (2 ratios, 2 sector
shaft diameters).
- The Ford steering box is internally (external housings are not shared)
a GM Saginaw manual steering box. Since the Ford steering boxes use
Saginaw internals, many GM parts interchange and some can provide
performance upgrades.
- 1971-73 Mustangs with power steering use either a Saginaw or Ford
integral power steering box.
- 1971-1973 manual boxes used a differently shaped external casting with
a 1 1/8" sector and 24:1 ratio. There also used a slightly different
frame mounting bolt pattern they won't interchange with 67-70 models.
- The 71-73 worm and rack assembly is identical to the 70-82 Corvette
piece. The Corvette sector (GM P/N 7812838) and worm (GM P/N 7812942)
will fit in 71-73 1 1/8" boxes if a new groove is scribed into the
Ford pitman arm that corresponds with the index on the GM sector and
if a Corvette coupler (GM P/N 7806391) is substituted for the Ford rag
joint. Provides 16:1 ratio rather 24:1 ratio. Also the flat Ford-style
sector shaft cover can be replaced with the 'Vette cover (GM P/N 7806748)
which has an integral bushing that lends additional support to the sector
shaft. The outer rim of the bushing support must be turned down to fit
in the Ford box.
- In addition to using a fast ratio steering box, you can increase the
steering rate by adding a Shelby quick steer kit (longer idler and pitman
arms - What cars did these come from?).
Related Magazine Articles:
-------------------------
1. "Steering Steady", Mustang & Fords, March 1993
The article covers a Global West steering box rebuild. Side articles
explain how a recirculating ball steering box operates and provide
a method for adjusting your steering box preload. Also presented is
a guide to identifying Ford steering box codes.
2. "Steerage Class", Mustang, February 1988
This article also covers a Global West steering box rebuild and
provides a list of steering box part numbers that are still available
(as of June 1987) from Ford. The article also lists some parts
interchanges and upgrades using GM parts.
3. "Pressure Sensitive", Super Ford, September 1993
This article describes a simple way to increase power steering feel
on vehicles equipped with Ford's non-integral power steering. The
approach is to splice an adjustable valve in between the supply and
return lines. Adjusting the valve varies the amount of boost,
increasing steering feel.
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