Steering Box Info
Steering Box Ratios (from Dan Jones, firstname.lastname@example.org)
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):
Short Shaft Boxes (SMA & SMB Prefix):
* 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:
- 1964-1970 Mustangs have two shaft styles:
- 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
2. "Steerage Class", Mustang, February 1988
3. "Pressure Sensitive", Super Ford, September 1993