These are some of the questions frequently receive from customers about the fast ratio conversion on 60’s, 70’s GM & AMC cars and trucks. Many of the conversions apply to Dodge pickup trucks, Jeeps, S10s, Blazers, Chevy pickup trucks and others
What is a quick-ratio conversion and why would I want one?
During the 1960s and 1970s, GM installed power steering gearboxes in their “A” and “F” body cars that had a very slow turning ratio. It took as many as 4 to 4½ turns of the steering wheel to get the wheels to turn from extreme right to extreme left. This slow turning ratio was most noticeable when parking or negotiating curves. Not only does it take more turns of the steering wheel to turn the wheels, it also takes more turns of the steering wheel to correct the direction of the car. This means that correcting quickly in a curve or taking evasive maneuvers to avoid an accident or road hazard takes longer with a slower turning ratio.
With our quick-ratio conversion, we install an O.E. factory quick-ratio worm gear and power piston in your gearbox as it is rebuilt. This will give you a 12.7:1 ratio and bring your car from lock to lock in 3 turns or less, depending on your car’s application. This will greatly enhance the car’s driveability, handling, and ability to avoid road hazards.
What is a "fast ratio" and what is a "slow ratio"?
In the 1960’s , GM used, almost exclusively, a 20:1 ratio power steering gear in most of their cars. Some of the exceptions were the 1969 Camaro and some full size Pontiacs that had the popular 16/13:1 variable ratio power gearbox. Those that came with 20:1 ratios, turn a full 4 to 4.25 turns lock to lock. The cars with 16/13:1 ratios turned from 3.50 turns lock to lock to 3 turns lock to lock.
How many turns, lock to lock, will I have if I have the "fast ratio" conversion done to my car or truck?
Generally, depending on the car’s need for internal stops, between 2.5 to 3 turns (lock to lock). Light trucks will generally be from 3.25 to 3.5 turns lock to lock with a 16/13:1 conversion. Late model light trucks through 1989 & later will be 3 turns or a little less.
Will I lose my turning radius?
No, the installation of our “fast ratio” conversion WILL NOT decrease your turning radius.
Should I replace my power steering pump & hoses?
This depends. If your power steering pump is leaking or more than 10 years old, we recommend rebuilding your current power steering pump. The hoses should be replaced if they are brittle, leaking or are more than 10 years old. I rebuild power steering pumps and can supply you with some new power steering hoses.
Can you change the ratio of my manual gearbox?
In many cases, yes, but remember if you do a fast ratio in a manual steering box it is “harder” to turn, NOT easier. Call to discuss your application.
Can I have the conversion on my original gearbox and have it returned to me?
Yes. Many of our customers prefer to keep their vehicle original. In many cases, your factory core can be made better than new. Plus, using your core ensures the factory stops are in the proper location for your application to prevent loss of any turning radius. If you would like to send your original gearbox to us, please see our shipping guide. Once your original gearbox is received, we will do a detailed inspection to determine if it’s re-buildable. If not, we can supply you with another gearbox matching the style of your factory gearbox with the proper stops. Most gearboxes that are closed and full of oil are rebuildable. If there is water in the gearbox it may be considered a “boat anchor” and not be rebuildable.
What is the difference between rebuilt and remanufactured?
The terms rebuilt and remanufactured are used to describe how a rebuilder or manufacturer wishes to present their product and are basically synonymous. Because there is no industry standard that sets parameters for what constitutes rebuilt or remanufactured products, rebuilders must only differentiate their products from new products by labeling them as rebuilt or remanufactured. Customers should ask a supplier of remanufactured products what they do to rebuild their products so they will know what they are receiving for their money.
Can I take a power steering gearbox from a late-model Camaro or Firebird and make it work on my Chevelle, GTO, 442 or GS?
There are several things to consider before attempting this swap:
- The Camaro/Firebird gearboxes have internal stops built into th gearbox to limit the amount of swing for the pitman arm (“F” bodies do not need as much swing as “A” bodies). If you install an “F” body gearbox on your “A” body without removing the internal stops, the turning radius of your car will be reduced and you will have a hard time making U-turns or parking.
- If a late model (1980 and up) gearbox is used, the flex coupling will need to be changed because it is smaller in diameter than the early models.
- The power steering pump pressure and return lines must be changed, since the late model gearboxes are metric and the early models are SAE. In addition, the pressure fitting on the back of the power steering pump will need to be changed to metric.
What do I have to change if you convert my gearbox to quick ratio?
NOTHING! Just remove the gearbox and ship it with or without the pitman arm attached and it will be converted and shipped back to you ready to install.
Can you convert my full-size GM car gearbox to a faster ratio?
Yes, however some full size GM cars will require a different housing. The replacement housing will be 100% drop-in compatible at installation, the differences are internal. This will add to the cost. Call us if you want to learn more.