Slant 6 mod's

Neither 3.08 nor 3.50 was available in the rear axles installed by the factory in that car—have you swapped to a different rear axle?

I disagree that the cam is the best place to start with your upgrades. You can greatly improve driveability and performance with upgrades to the ignition, induction, and exhaust systems without touching the camshaft.

I also disagree that the mini starter sounds better (than a properly built Chrysler starter), but that's of no real consequence.

Really, what to do and in what order depends on your specific goals for the car's performance. What (exactly) do you want it to do differently than it does now?