The Right Turn

Does this sound familiar? You install a wild big-block in your ’69 Chevelle, stand on the gas, and go happily down the street spinning the hides. Next thing you know, your baby gets away from you because you’ve been sawing at that turtle-slow steering box. It’s time for quicker steering to match that increased power. Installing a late-model G-car steering box into any early Chevelle will give you the late-model steering feel.

That legendary GM interchangeability is also true of steering boxes. The Saginaw 800–series power-steering gear has been in use since 1965 in fullsize and intermediate GM products. These boxes came in a plethora of gear ratios ranging from a slow-as-molasses 20.0:1 to a very quick 12.7:1. To be specific, you can interchange a late-model 12.7:1 box into any ’65-’77 A-body GM vehicle.

But this isn’t exactly a pure bolt-in. There are a few changes that we will have to deal with to install one of these boxes into our ’65 El Camino. The preferred steering gear can be purchased directly from your local GM dealer under PN 7839897, but you’d better stop by the bank on the way to the dealer to take out a loan. Being resourceful hot rodders, we would prefer to work a little for our bounty. The preferred high-effort, quick-ratio steering box was offered in the following cars: the ’83-’88 Monte Carlo SS with HD suspension, the ’83-’88 Hurst Olds/Cutlass with HD suspensions, the ’84-’88 Buick Grand National/Regal with FE2 and FE3 suspensions, and the ’86-’88 Pontiac Grand Prix with touring suspension.

Working with your local wrecking yards, you can use the Hollander interchange number 1282 to identify this given steering gearbox. Or, as you’re scrounging around in search of this trick steering box, look for the “YA” stamp that is located on the end cap of the steering box. This stamp is very delicate and is easy to wash off, but it’s the only way to identify the box at a glance.

The next step after acquiring your YA steering box is to pick up the pieces necessary to install it. We spoke with Tom Lee, head of Lee Manufacturing in Sun Valley, California, who has been building these boxes for racing applications for many years. Lee offers all the pieces required to install the late-model box into your early iron. Or Lee can build a completely blueprinted steering gear in any gear ratio, steering effort, and configuration to bolt directly into your Chevelle. He informed us that the YA box is a perfect choice for the early A-bodies. However, there are a few things that you need to know.

First, employing this box will lose approximately 15 percent of your turning radius over the stock steering box. However, you will probably never notice. This is because very few of us are still running around on the stock F78-14 tires that came on the early Chevelles. When you install the wider tires and wheels on your car, the tire will contact the frame before you run out of steering gear. Next, Lee offers adapter fittings that easily press into the late-model O-ring–type power steering–line ports. This converts them back to the standard 37-½-degree SAE double flare–type lines.

Late-model steering boxes also utilize a ¾-inch, 30-spline stub shaft, while early boxes are equipped with a 36-spline, 13/16-inch shaft. Lee offers a steering coupler (as known as a rag joint), which has the late 30-spline count with the proper bolt spacing to line up with the early steering columns. To use this coupler, you will need to drill out one of the bolt holes in the steering column to 3/8 inch. On the early columns, both attaching holes are 5/16 inch.

Later steering columns use 5/16- and 3/8-inch mixed fasteners to phase the steering gear to the steering column. It is a simple task to drill out the one hole. First, make sure that you have centered the steering gear and indexed your steering wheel properly. This will identify which hole in the steering column needs to be enlarged. Also, this will phase your steering system from now on. However, if you don’t want to drill on your dead original A-body, you can use one of the original 5/16-inch bolts out of your original rag joint and replace the 3/8-inch shoulder bolt in the new steering coupler.

Installing the flare seats is a snap, and the instructions that Lee supplies are very clear. The seats are a press fit and are installed by using a ¼x2-inch bolt. Spinning a nut about 3/8 inch onto the bolt creates a great pilot punch to install the seats. Install the aluminum seats without the stock O-rings and drive them slowly in with a hammer until they seat, making sure they are started straight before tapping them in place.

This brings us to the power-steering pressure and return lines. The factory high-pressure lines are designed to withstand the 1,800-plus psi that can occur at full lock. The factory lines might be ugly, but they will work just fine. On the return line, you must use a good, high-quality Weatherhead-type power-steering hose. Don’t skimp with 3/8-inch neoprene fuel line since this type of hose has been known to fail, squirting hot oil on the headers, which could result in a fire.

On the pressure side, you must install an 18mm flare nut on the pressure line. This requires you to either double-flare the pressure line with the new fitting installed or locate a hydraulic-line supplier in your area that can do this for you. It must be a double flare or the line will fail!

Our El Camino sported a ’96 GM Performance Parts H.O.T. LT4 outfitted with a complete Corvette accessory drive. This accessory dress uses the O-ring–type power-steering lines, so we only had to install the flare seat on the return side and fab up a return line to the Corvette power-steering reservoir. These O-ring–type lines are a nice upgrade in preventing leaks. The best that we can come up with is that GM changed over to the O-ring–type seal in the late ’70s. It wasn’t a clean model-year swapover.

Lee also informed us that the early Chevelle power-steering pumps produce the proper volume and pressure to support the late-model box. You can vary the pressure and volume to change the feel and response of the steering gear, but we will leave this trickery to the experts. You can contact Lee Manufacturing for any modified gear, pump, and the like for any custom applications. Lee also recommended that we drain the original power-steering fluid and replace it with new fluid. Power steering is a high-pressure hydraulic system that can generate tremendous amounts of heat when taxed. Don’t run standard automatic-transmission fluid in your power-steering system. ATF doesn’t have the lubricating additives necessary for good pump life. The best fluid to use is good old GM power-steering fluid, which can be picked up at any GM dealer.

If you’re going to attempt this swap yourself, make sure you can handle it. You will be dealing with high-pressure hydraulic systems that are precision components. The failure of any of these systems could cause serious bodily injury. The best insurance is to have a factory service manual and a complete understanding of the task at hand before getting greasy.

This story was not intended to be a step-by-step guide to replace your steering box. Instead, we decided to illustrate the key points necessary for the swap. After we installed the new box into our car, it took us a while to keep from turning into curbs. Going from a 20.0:1 steering ratio to a very quick 12.7:1 is somewhat of a night-and-day change. The feel of our El Camino will never be the same. Also, if you have any suspension upgrades, you have never really been able to appreciate the improvements that good bars, springs, and shocks have given your early iron until you give them the right turn with a quick steering box.