Factory Steering column length?

I did a Flaming River. Expensive but well worth it. I think they make a drop in for your 70 that uses the factory clamp. They didn't for my 69 but the B-Body one was a drop in with a trimming of the D-Shaft. They include the U-joint, wiring adapters, and the column have about 1.5" of slide like the factory one. Down side is the factory steering wheel doesn't fit well in that the column is bigger in diameter. If your going aftermarket steering wheel than that's not an issue.