IMO, yes these specs are applicable to most E bodies or any classic for that matter. The exceptions being cars with manual steering or bias ply tires. Manual steering requires a fair amount of effort so you want to keep caster to a minimum if not negative. Additionally, bias tires will not tolerate as wide a range of adjustments without showing odd wear. Radials, on the other hand, can absorb a much wider range of angles before they wear improperly.
Your welcome to provide these specs to your guy. Don't be surprised if he poo-poos that much caster. There are a lot of alignment techs out there that don't agree with that much for street cars. The arguments against high caster angles are usually the increase in effort it produces and the fast return to center. I think both are positives in a classic mopar. Even with the offset bushings and adjustable struts you may not be able to get up past 5*, but that is still a decent number.
For truly high performance settings, the desired target for caster should be equal to or slightly greater than the spindle axis inclination (or kingpin angle). The reason being that equaling the SAI allows the caster angles to offset the SAI angle to pull higher camber angles the harder you turn. This allows the tire to remain more upright in a corner as the body rolls around it. By creating a more dynamic change, you don't have to dial in as much static angle, so you can run less camber initially while gaining more camber dynamically. Low caster/camber angles do not compensate for the body roll as well and will begin to pull the tire at an angle minimizing its contact patch.
Its not always easy to envision, but the front suspension in moving in three different planes simultainously. Getting all these planes to play nice together is the challenge to making the suspension work for you instead of against you.
