The interchange is to very early 164's w/o power steering, to the majority of 164's which do have power steering, and to late 140 automatics, many or most of which had power steering for 1974 only.
The ratio is faster in the power boxes and they can be run manual style (but they are huge).
The ratio is variable (faster out near the locks, & yes, this can easily be engineered in) on the rare early 164 manual boxes.

Topi/TRS used to offer a faster ratio 140 steering box. I have no idea what that was. Gears from something else (122, 2002?) in a 140 box, I am told. He called out 3.5 turns with full use of the existing lock. Stock was 4.0. We could ask him if Dave Barton didn't drive him out of business. On the Swedish boards, I have not seen a conversion method used, but I've typically stayed in the engine forums.

One thing to understand in the bigger context of car enthusiast driving, is that the ratios of cars have decreased by about forty percent, since the 140 was engineered- from the 140 being on the quicker end of 17.5-24:1, to modern cars that are 11.5-14.
To some that makes it seem vague and slack.
At the time, there was more driving at low speed and on gravel, and in Volvo's case certainly testing in snowy driving conditions. The slow ratio makes it much easier- more precise, in fact- to make small corrections when at the edge of traction at low speed.
I'm familiar with the Hyundai Elantra Touring which has 12.2:1 steering, IIRC. Whatever it has is much faster than a 140. It also has electric boosted power steering which has inherent major "inertia feel". Comparing driving them in snow and ice, you loose traction with the Hyundai, and you are going for a ride.
Put it another way, in the Volvo I can feel and correct several times, no exaggeration, before the first correction input of the Elantra replies back to me via "seat of the pants". Also, and inch and half motion of the Elantra steering wheel rim is enough degrees at the tire to break traction. Very easy to over correct and your hand motions have to be miniscule and sensitive. All while the steering fights you with the effect of having a 40 lb flywheel in the column somewhere (and worse, one that comes and goes!!).

To me the Volvo has *vastly* better steering. The 544 is notably faster and lighter than the 142, however. The 142 is only 350lbs heavier, (2280 to 2630) but feels it. I find myself needing to crank in more lock midway into the corner if I've been driving the 544 and switch to the 142. So, not only is it heavier, but it's slower as well. The 140's have several more degrees of lock angle, and only a half turn more rated lock to lock of the wheel, so on paper...? I'm surprised, but it's unmistakable, and the wheel base is the same

But, anyway, if you are used to the Hyundai, and driving on dry pavement with grippy tires, you might say you liked how little steering wheel motion was required to zip it around 90* turns. You might even like how it feels magnetically dampened when holding a straight line, and lightens way up when you begin to "use" it. I don't personally, but the car magazines all did, or claimed they did. It also has a combination of trail and caster which make it seem like a guttered bowling ball- requiring work to get it to climb out of its straight ahead groove, and all too willing to "fall back into" said groove.


If I were to get organized and tool up to make new fabricated front spindles- this is not unheard of- I would
A) raise the hub centre for about 1.75 lowering with full stock suspension travel
B) raise the upper ball joint height substantially for a camber curve which goes fairly sharply negative (at least compared to OE) on the outside wheel in cornering/roll.
Lastly (and on topic here):
C) bring in the steering arm tie rod attachment closer to the SAI pivot axis, for slightly quicker steering. I'd need to study it a bit, re: bumpsteer, but a little toe out during roll would be just fine- more ackerman. ;)

Potential fabrication of 140 spindles has been simplified by Ford using 5 on 108mm bolt on bearing units on just about everything passenger car that they build.
So the spindle can be a much simpler build because you are not building the bearing unit in- merely allowing a flat place for it to bolt onto.




Ps. You did say exhaustive... lol. Merely fulfilling your request.