I bet the casting numbers are different on the older ones vs. the newer style. But I don't know what the numbers are; or how many different versions there might be. I'd kinda expect L and R for 1500s and LD 2500s; perhaps another version for HD 2500s and 3500s.
Well, it does look like the 97 1500 4x4 got improved turning radius:
Source:
https://media.chevrolet.com/dam/Media/documents/CA/Archives/EN/Vehicles/chevy_truck/1997C-K.html
"
NEW FOR 1997:...
...* Improved turning radius on all 1/2-ton 4x4 models..."
Well, that means that the K2500/K3500, and all C models don't need to checked for tighter-turning knuckles. Be nice to see the casting numbers for the '97-up K1500 knuckles, though.
My question was more based on nabbing an OE junkyard correct box to send out to a company for a quality rebuild at a glance. Unless part numbers on the casing itself could clear that up.
I would not expect a casting number to have any relation to how the guts of the box are specified. The housing with the visible casting number could have all sorts of different parts loaded inside it.
THREE things in a steering box that are important:
1. Steering-gear RATIO. Typically 12:1--22:1. They can be single-ratio or variable-ratio, where the ratio changes with steering angle.
2. Steering STOPS. Controls the angle that the gearbox can be turned. With GM cars, you typically see somewhere between 30 and 45 degrees. For example, 64--72 Chevelles need 40+ degrees of gearbox angle, the steering stops are when the steering knuckle hits a reinforced section of the lower control arm. A Second-Gen Camaro has the stops built-into the gearbox limiting travel to 30-something degrees. The farther the gearbox turns, the sharper the steering knuckle turns...until the steering linkage binds.
3. Torsion-bar DIAMETER/STIFFNESS. Small torsion bars provide lots of assist, but give little feedback. This gives "one-finger steering" that feels over-boosted and completely dead. OTOH, a stiff torsion bar gives lots of feedback, but requires more effort than Grandma is comfortable with.
And, of course, GM isn't very good about providing any of that information to the consumer. They install a steering box that THEY think you'll like, and if you don't...tough. I have no idea how you'd go about selecting a "good" box for your needs; and of course the boxes with best road feel and fastest ratio are going to be scarce--perhaps they'd be used on the 454 SS trucks.
You're kind of at the mercy of the specialist rebuilders; you send them a box, and hope they put the "good" gear ratio, the proper stops, and the "good" torsion bar into it before they send it back to you. And you also hope that their idea of "good", and your idea of "good" are the same.
