What is this box good to use on: Is it a quick ratio? The shaft turns about 3 1/3 turns lock to lock clockwise rotation. This SG has the number 605 cast into the box. It's not the same type as the Tri five's use. It's a little smaller than the standard GM gear Box .The casting number is 7819688 with the Saginaw logo. The gear housing cover in ring retained

The 605 is not a very modern power steering gear. It was developed by Saginaw Steering Gear in the late 70s as a low cost, somewhat light weight power steering gear for use in GM's intermediate size cars. It does not have recirculating balls, it has an acme screw that translates the rack piston. So the gear has more internal friction. I doubt that it even had a fast ratio (12.7:1) available.

The new model 600 NASCAR gear is a much better choice. And it is available with a 12.7:1 fast ratio.

JIML82

It is the gear box that "55 - '57 chevy use to convert theirs cars to modern gear box and a streeing column thats not one piece.
I have converted them myself.
Sell it on ebay as the 605 for '55, '56, '57 chevy, and you mite be amazed at what you'll get for it!
It was used through the 80's on most intermediate GM cars.
Pat