Author Topic: Trying to figure what steering boxes I have ???  (Read 580 times)

DAVEN1256

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Trying to figure what steering boxes I have ???
« on: February 22, 2017, 01:11:45 AM »
I have a '68 with power steering. I've been trying to make up my mind whether to have a 12.7:1 fast ratio conversion by Powersteering.com done to my original power steering box.....or to go with the Cardone IROC box (pn 276550), also with a 12.7:1 ratio. The Cardone 276550 box is the one I always see mentioned as "the one to get" for much better steereing.

Ideally, would have prefer to keep my original box with new innards but that is a whole lot more expensive than doing the Cardone conversion when buying the Cardone box at a local parts store ( no shipping something very heavy each way).

Not having made up my mind, I bought a Cardone box from Advance Auto Parts just to compare to my original box. I was curious as to the ratio of my original box and wanted to be sure the Cardone box was actually the 12.7:1 ratio.

http://shop.advanceautoparts.com/p/cardone-power-steering-gear-domestic-27-6550/3791467-P

Doing some checking using a homemade degree wheel and a protractor, these are the results I got. They may not be dead nuts but they are close.
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My original box: Number of turns lock to lock: 3

One full turn of input shaft = 20.5 degrees of output shaft turn

Input to output shaft ratio: 17.5:1

Total degrees of pitman arm travel lock to lock: 62 degrees
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Cardone 276550 box: Number of turns lock to lock: 2 3/4

One full turn of input shaft = 23.5 degrees of output shaft turn

Input to output shaft ratio: 15.1:1

Total degrees of pitman arm travel lock to lock: 65 degrees
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I see a lot of conflicting information about what an original '68 power steering box's ratio and number of turns lock to lock should be so I don't what I have here. I'm sure it is the original box.......Any ideas if this is a standard power box or possibly a fast ratio?........For what it is worth, I have the long pitman arm (5.8 inches center to center)

I was surprised that the Cardone box's ratio was so far off. Has anyone else bought one of these and found out they were not the 12.7:1 ratio? Maybe I didn't get the right one.

Thanks.....Dave

elcamino72

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Re: Trying to figure what steering boxes I have ???
« Reply #1 on: February 22, 2017, 03:27:29 PM »
I'm referring to my notes from my conversations years ago with Jim Shea (retired Saginaw steering gear).  1968 had one steering box and it was 17.5:1 with 31 degrees of travel from center or 62 degrees of total travel as you have measured you box to be. 

One might think that all first generation power steering boxes are the same but they are not. 

1967 had two boxes, both with 17:5:1 ratios but one had 87 degrees of travel while the other had 70 degrees of total travel.

1969 was a variable rate box 16-12.4:1 with 64.5 degrees of total travel.


DAVEN1256

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Re: Trying to figure what steering boxes I have ???
« Reply #2 on: February 26, 2017, 02:20:58 AM »
Thanks for the info about the '68 factory ratios. You info matches my box right on the money.

Since I only got one response on this, I am starting a new thread concerning the Cardone IROC box.

Thanks again.......Dave