I also have a 67 Impala and would like to get the Lares box from Rockauto . 3 turns lock to lock, but it says you need a different coupler rag joint, But it doesn't say what one. Also do the stock hoses fit this box, and is it the same outside profile. My headers had to be formed in for clearance around the box (very close). Rockauto doesn't seem to have tech support to talk to. So any input would be great.
There are adapters to go from the SAE or "English" steering boxes to mate to the newer metric boxes. Different spline count and shaft size is what you are compensating for, and this is a very common upgrade. Same for the hoses. You have a Compression Flare fitting on your old SAE box and newer Metric boxes use O-rings to seal. There are adapters to mate your old hoses, or the best solution is to have new hoses made at NAPA to match length and what you have for fittings.
Real problem that no one addresses is that these new Metric boxes are smaller (800 series instead of the heavier duty and older 600 series). These new metric boxes are off of 3,200 pound Monte Carlos, or 2,800 pound third gen Camaros. Not the strongest match for a 4,200 pound lead sled of an Impala if you are going to push the barge by trying to autocross it.