I searched a little more on-line and a reversed corvair box has 3 1/2 turns lock to lock, which is one full turn less than the original steering box.
The stock corvair box would mount top of the frame rail and has the pitman arm on the engine side. (in the corvair the box is on the side of the frame and the pitman arm is underneath).
Here's the original coravir box:
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http://www.speedwaymotors.com/eccStoreFront/product_images/2005/91032219_1_T.jpg[/img]
When you reverse the corvair box, it mounts and works just like the original AD box, on top of the frame with the pitman arm on the outside of the frame. All you'd have to do is cut the steering column, put a bearing in the mast jacket and use a rag joint or borgensen joint to connect the stock original steering shaft to the reversed corvair box.
Here's a reversed box:
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http://www.tperformance.com/category_pics/large/TP23T80.jpg[/img]
Reversing a corvair box is very easy if you find one in original condition. Basically you take the worm gear out, put a 15/16 freeze plug in the hole that the steering shaft used to stick out of, then you drill a 11/16th hole in the threaded cap at the other end of the steering box, put in the seal from where the steering shaft used to come out of the box, put worm gear in the box, put the bearing in place, put the newly drilled lid on, and you are up and running! Here's a link to an online article photos on how to reverse a corvair box.
I've found reversed corvair boxes on the internet for around $150, and used non-reversed ones for around $75, which is not bad considering a rebuild kit for the original box is around $120.