Some time back there was a thread in the Willys forum worth reading on underbody paint, and it seems the factory applied quite the variety, making it hard to determine what's "correct" or not for any span of production.
I ended up with a quart of the darker grey dash paint that was mixed with just one size metal flake instead of two, that tinted my underbody from the bell housing back. Front wheel wells & inner front fenders body color. All of the above base/clear was basically the tint for a mildly stippled chip resistant base.
Body color went on base/clear.
I wanted it to look correct but none of this is really "factory correct" except for the metallic size & body color. I have two reasons for my choices. I stripped my Healey in the early eighties for a "correct" enamel repaint. I only drove it a couple summers, the remaining time stored inside. Seeing how it's aged was a big factor.
Also, my Aero has had a tremendous amount of work put into it (as will yours). I see no reason to use anything but the most durable coatings I can source to protect it. I got my fill of compounding dull paint when I was younger, and judging for me is a non issue.
