Radials do like minimum toe-in. The whole situation of toe-in is that as the wheels roll against the pavement, a force is piut on the steering system so toe-out the front wheels. So the static pre-load is there to compensate for that. Such that "rolling toe" (which some alignment machines used to have) is pretty much zero.
The other thing, in the earlier 1980s when all of the OEMs went to a M+S tire, was that the tread segments also fles when they touch the pavement. If the tires were not rotated every 6K miles, they'd get a flaky wear patterns which the prior "rib tread" tires did not. We're past all of that stuff now.
Those offset upper control arm bushings were around long before radial tires came to the USA. Their intent is to compensate for "sag" of the front crossmember. Seems that Chevrolets since 1854 have been known for that, especially earlier-'70s Chevelles with 454s in them. But their offset can be used for other reasons, too.
When the cars were designed, they had TWO caster settings. One was for manual steering, which was about 1 degree negative, for easier steering. The other one was for power steering, which was 3/4 degree positive, for better highway stability as the power assist took care of any extra effort to turn the wheel.
Many hi-caster front ends can have issues. Simmy, for example, which requires the addition of a steering stabilizer item on the tie rods. As some foreign brands and some GM cars had in the earlier 1970s. Not sure at what settings those are needed.
ONE thing about Chrysler front end geometry is that their camber angles when the wheels turn result in negative camber on the outside front wheel and posotive camber on the inside front wheel. What this does, as the car leans, is keep the wheels more perpendicular to the road surface, especially the outside wheel. Even bracing the outside tire a bit with still-negative camber. Adding caster to a normal front end does this too.
When I had the caster maxed (about 2 degrees +) on my '77 Camaro, with the TransAm WS-6 sway bars, the car did not lean, so I started to get more "edge wear" on the outside of the tread of the front tires. Many people perceive that they can't drive down the road without 8 degrees of caster, but then there were some people who perceived they needed a SBC 4-bolt main block just to drive to the corner store for some milk. On Gen II Camaros, it takes a special set of upper control arms to allow for 8 degrees of caster and still have camber in spec.
To me, the best set-up for a C-body front is first to have a set of good, HD shocks on the car. Then start with the alignment specs at factory settings, with the toe-in minimized for radial tires. That is pretty good, to me. IF the alignment machinedoes not have any specs for the vintage Chryslers, then +1 degree caster, Zero camber, minimum toe-in. At factory ride height, with the rocker panel parallel to the road surface.
Take care,
CBODY67
