I bet it'd run hotter in Riyadh!

Seriously, it sounds like guys are discounting your issue but they are mostly speaking from experience. Factory gauges can be quite a ways off.
It sounds like you have a big enough radiator if you can get air to flow through it. Blazin' Bob doesn't know how to spell shroud, but he is right that a too-slow water pump can reduce cooling capacity. Chrysler engineers did not take a one-size-fits-all approach to engine cooling. The pulley ratio for a car originally equipped with 4.10s is different from the fan ratio for 3.23s, at least it has seemed that way to me.

Look at the fans used. Some had quite a few blades, some had five. I'm thinking that for traffic many blades are better, while at highway speeds they may act as a roadblock to airflow. A shroud makes the fan more efficient, it should be there unless there is a compelling reason for it not to be.

The factory took pains to make sure that the air striking the front of the car actually went through the radiator and not around it. Many cars had rubber seals in the hood region, or around the radiator opening. You may want to check what your car came with and if they're in place.

There are no manifold heat risers on 440Source, Edelbrock, and Trick Flow heads. I would doubt that the higher performance heads have them either.
Your car should not smell like gasoline when idling or sitting. I do not believe 6-pack tuning is for the novice, although the Manifesto is pretty complete. I'm sure the experts here will amplify my statement.

Retarded timing can cause overheating.

RB engines are physically large and can stifle airflow through the engine compartment.

But first you have to measure the situation and see if it is a real problem.

Good Luck! And don't let the Religion Police get you!

R.