1968 Chevy Chevelle - CPP Saginaw 600 Steering Box Upgrade

There's no getting around the fact that our muscle cars are antiques. Our minds play tricks on us, recalling our favorite cars and the antics we played as if it happened yesterday. News flash: You aren't a teenager anymore, and your hot rod isn't showroom fresh, either. In those intervening years, your steering box has worn, perhaps even to the point of a dangerous failure. Moreover, ongoing improvements in automotive engineering have made us accustomed to razor-sharp handling in our ordinary commuter cars.

One of the big trends in hot rodding is a conversion from a traditional steering box, to rack-and-pinion steering. The benefits of this include lighter weight, a more compact design, and incremental improvements in steering feel and response. There aren't really any significant downsides to a rack-and-pinion conversion, except for cost (kits typically cost anywhere from $1,200 to $2,700), and in some cases, a reported reduction in turning radius.

The price gap between a rebuilt stock steering system and a rack-and-pinion conversion is huge, and this has allowed a lot of products to filter nicely in between. Of course, Detroit automakers and their suppliers-such as Delphi-haven't exactly given up on the tried-and-true recirculating-ball steering box. Current production trucks still use modern variants of the steering boxes that were originally used in the 1960s and '70s. And as anyone who's driven one of Detroit's modern trucks can attest, they aren't the numb-feeling slouches they once were, and it's all because of the cumulative improvement employed in today's steering boxes.

This ensemble with components from CPP (Saginaw 600 steering box, U-joint, rag joint, steering shaft, and O-ring adapters) totals $591, and comprises everything we needed to update our '68 Chevelle to a modern, 12.7:1 variable-ratio steering box.

The Delphi Saginaw 600 Series box is one such animal, and is a popular upgrade sold by many companies filling the void mentioned above. The Saginaw 600 box is far more durable, and stronger than the OEM Saginaw 800 box found in cars like our 1968 Chevelle. It's also 5 pounds lighter, and has a performance-oriented 12.7:1 steering ratio that gives it the same rapid steering input of current rack-and-pinion systems. Most Saginaw 600 boxes are brand new (such as ours), and have a tight, crisp feel only available from a new piece of hardware. That's perhaps the biggest reason the Saginaw 600 is the steering gear of choice in NASCAR race cars. Lastly, it bolts right in-if you order the right accessories.

That last one's the rub, because you could be in for one heck of a trial-and-error session if you're not up on the 600's technical attributes. If you're like us, you aren't familiar with the requirements to make a successful Saginaw 600 upgrade to a '64-72 GM A-body (Chevelle, Cutlass, Tempest/LeMans, Skylark). That's where the folks at Classic Performance Parts (CPP) come into the picture. They offer the Delphi Saginaw 600 box as an outright, standalone purchase ($399), but they have also developed all the pieces and bits you need for a successful, first-try conversion. We've been down the road of cobbling together the necessary fittings, U-joints, shafts, and fluid lines, so it was a welcome change to have the clear path laid out for us by CPP, who have already been down that road.

The tale of the tape is that we spent a total of $591. That netted us the Saginaw 600 box and all the associated pieces we needed for a trouble-free, half-day installation. On the performance side, we got a vastly improved steering feel that can go nearly toe to toe with a modern rack-and-pinion conversion for anywhere between one quarter to one half the price of a rack-and-pinion conversion. For us, it was the right trade-off for our mostly street-oriented Chevelle project car. Now it's your turn!

Our starting point is this engine bay photo showing the stock steering shaft and factory Saginaw 800-series 16:1 steering box. Note the wear marks on the stock shaft where it touches the headers. This is virtually impossible to avoid on big-block Chevelles with stock steering shafts. There was no better time to fix this, as it was causing a bad vibration in the steering wheel.	Use a pitman arm puller to remove the arm from the tapered splines on the old Saginaw 800 steering box. Remove the old steering shaft from the car, disconnect the fluid lines, and unbolt the old box.	Snake the new Saginaw 600 box into place, and bolt it up using the original bolts.
Double-check that the pitman arm is centered properly, then use an impact gun to seat the pitman arm onto the tapered shaft.	The original Saginaw 800 box has 37.5- degree SAE double-flared compression fittings that are incompatible with the metric-style O-ring fittings of the late-model Saginaw 600 box. In the past, some suppliers have required the use of a conical flare seat adapter, which is tricky, and can lead to leaks. CPP makes these screw-in adapter fittings (PN 605SOL) that allow you to connect your existing high-pressure and return fluid lines to your power steering pump without drama.	Your feed and return lines just wrench right on with a 5/8-inch tubing wrench. In the past, the incompatibility of the older flared compression-type fittings and newer metric O-ring fittings has been a big obstacle to a late-model steering box upgrade.
The newer Saginaw 600 box has a 30-spline 3/4-inch input shaft; the original was a 36-spline 13/16-inch shaft, and the rag joints are not compatible. The new CPP rag joint (PN RJC-730R) makes the conversion a snap, and goes on with a 3/8-inch socket wrench.	You can tighten the CPP Max Clearance shaft to the rag joint coupler by tightening the set screw into the flat of the "D" section, but the safest thing is to mark the position of the set screw, and drill a recessed locking hole for the set screw to mate with.	After marking the location of the set screw lock hole in the flat of the "D" section, drill it out carefully. CPP does not predrill the set hole-or the corresponding safety groove in the following photos-due to small variances in each car. These photos do not show it, but you will need to mock up, mark, and double-check the location of these mods at least once.
Here's the mark we made on the top of the Max Clearance shaft where it enters the new U-joint at the steering column. The marker represents where we'll grind a channel for the pinch bolt, which doubles as a safety lock in the groove we're going to make. The U-joint replaces the 40-year-old unit on our original steering shaft, and is a tight, precision piece of hardware.	Using a die grinder, grind a shallow groove in the Max Clearance shaft where you made your mark.	The CPP U-joint is then slid onto the steering column. Don't tighten anything just yet.
Now's the time to attach the Max Clearance shaft to the U-joint and steering coupler. Before tightening anything, check the phasing of your steering, the position of your steering wheel, and the position of your wheels. Tighten everything, then double-check your work. If you've done everything right, you may get extremely lucky and not need an alignment to tweak the toe-in or steering wheel angle, but that's not likely.	Wow! Look at all that extra header clearance we picked up. Too bad we didn't do this before we hammered on our 1 7/8-inch Stainless Works headers. Actually, we could probably afford the clearance to step up to some 2-inch headers now. Now all that's left to do is top off the power steering pump with some fluid and get that alignment done.