sweet56olds

I have two steering boxes and one is a 605. I have noticed that the two have different spline diameters where the pitman arm bolts on. Both of these are newer boxes with the one with the larger diameter pitman spline being a mid 70's and the 605 with the smaller spline being a late 80' orearly 90's box. Will my stock PS 56 pitman arm bolt to either one of these?

Rocketowner

The original will be a Saginaw ,and I believe 1956-1960 are the same. Maybe someone else can look up on parts exchange book and see if any others will work! I know some years of Pontiac and Buick would be a good candidate. Larry

steverw

Long ago my best friend and myself put a 605 in his 56 Chevy. I dont know if your Olds box is the same as the 56 Chevy box or not. It seems we had to put his original pitman shaft into the 605 box. It actually worked very well, but that was in about 1987, so i cant remember specifics. Im sure you can find some articles on it. I believe some companies sell the 605 conversion. Again not sure if the Olds and Chevy boxes are the same, but i would say theres a good chance they are. Check with Danchuck or some other Chevy resto supply, maybe they can help. On the pitman arm I think you would just have to pull yours and see if it fits, or use a pitman arm made for that specific steering box.

sweet56olds

My Olds box has a rag joint not a solid shaft like the 56 Chevy. I have two boxes at work with two different pitman splines. I just was hoping someone knew which one will fit the 56 Olds pitman arm. I do not mine out of the car so unless I can figure this out I will have to pull it out just to measure it.

steverw

There are some articles on the H.A.M.B. on this. I looked today, several say your pitman arm will fit the 605 box. There was one member that said he has some 605 boxes set up for a 56 Olds, but there was no contact info for him that i could find. I wrote down his forum name but its at work, Ill try to post it here tomorrow. One said he has the 605 on his 56 Olds but where the front bolt goes the frame needs to be altered just alittle, about a 2"X 2" patch. I Googled "605 steering gear box in a 56 Olds", thats how i found this info. I found the same article my friend and I used almost 30 years ago for his 56 Chevy.
Steve

sweet56olds

Thanks for the info. I found the same info but am still perplexed about the pitman arm. An article on here suggested a box off a Chevelle and was supposedly a direct bolt using my PS pitman arm. The 605 has a different size pitman spline. Now that is two different articles saying they both work so am just going to pull my pitman arm off and take it to work where I have both boxes. Thanks for all the responses. I will post what I find out for anyone else that is curious.

steverw

I can tell you the 605 on my friends 56 Chevy worked out great. It was a relativly easy conversion. At first it turned way to easy, you could literally flip the wheel with one finger and it would spin all the way to the stop. A pressure valve change in the pump fixed that problem.

sweet56olds

I think I know what the problem is. Those that are saying the pitman arm will bolt right on the 605 must be using a manual steering pitman arm. They must have a smaller spline. I am trying to locate a used one but no luck so far.