Another Steering Box Thread - Small/Large Sector Shaft

First I'd like to confirm that a 1972 would have come with a "Small" [1-1/8"] sector shaft, correct? Across the splines on my original box is about 0.030" over 1.125", which makes me ask the question.

Secondly, assuming I had a small sector shaft car, what would it take to upgrade it to the larger 1-1/4"? Is it simply the right box and associated pitman arm from a '73+ Ebody?

Going with the idea that bigger is better with this component.

When I bought my box from Firm Feel I got the large shaft with matching quick ratio arms. It was a easy way to upgrade and get firmer steering on top of it.

For a ebody or 70-72 B body you can switch large and small spline with the appropriate pitman with no other changes.

Also to consider the price of Moog large diameter pitmans compared to small ones.

With your training, that's not something I would have expected to hear from you, and I suppose you can tell where I stand on the issue.

I have sheared off a sector shaft before and twisted one [Jeep], it seems silly to put a smaller, critical , component in at this time.

Past experience is keeping me from trying to nerd-out over this particular topic.

Just don't take your Cuda offroad.

You dont measure the splines you measure the shaft.

Im rooting for you to succeed on the Borgerson unit Goody!
Because if and when you get it all properly functioning, I'm going to blatantly copy your setup haha!

It would be awesome to get rid of another 10-15 pounds off the front end.

You lost me, but maybe that was the point.

It's those 42" tires that will kill it.

for my 65 coronet, which shares most of the same suspension stuff, that is all I did.
ordered up the newer box, which apparently is the same up to the 89 full size rwd cars and the 73 and up pitman arm and it dropped in.

I was concerned about indexing, but even that lined up the same with no issues.

Per my understanding the larger shaft uses the more common and less expensive pittman. Is the larger shaft better beside cost? IDK. When I had my box rebuilt I chose the larger shaft at no added charge to use the lower cost pittman. I figured the larger diameter was a possible strength bonus despite the slight added weight... and happy with lower cost.

I have the larger shaft in my Cuda, seemed to work fine. Now I wonder, why did Chrysler go to larger shafts in 1973?

Iirc, C bodies had the larger shaft for a few years prior.
Then the B vans came out and they used the same shaft. At that point it may have just become more cost effective to standardize across all platforms.