The goal is a faster steering ratio / stiffer feel in my 91 300SL track day project.

There are many options, some sort of MB interchange, a GM box or even a rack and pinion conversion. The MB box might be hard to find and $ , Gm boxes while available in many stock and aftermarket ratios , but they have a larger distance from the output shaft to input shaft and might require floor mods, a rack and pinion would be great but snaking a steering shaft to the gear might difficult and I think there will be oil pan interference.

Does anyone have a good steering box reference showing different box models ? I've poked around the excellent 124 performance web site but have not comeup with the info I'm looking for.

I've seen partial breakdowns but nothing specifically showing the steering valve. Most American steering boxes use a torsion bar in the rotary valve, ( 70's and 80's Chryslers used a reaction disc , I've seen industrial stuff use small leaf springs. ) This torsion bar dictates steering feel, a stiffer bar reduces power assist.
To speed up the ratio, I'd need a box from a 500E sportline or similar.

From a for sale post

"" Ratio 14.6-16.1 = Coupe standard box
Ratio 13.9-15.3 = Sedan & cabrio standard box, coupe Sportline
Ratio 13.3-14.6 = Sedan & cabrio Sportline box (<-- this is what I'm selling) ""

However, the box has mounting bolts in the wrong place for a R129. I might be able to use the internalls but finding a 500E might prove difficult.

Thanks