Batman (1940) #458, Pg. 22 by Norm Breyfogle & Steve Mitchell (Batmobile Mk.III) 11.5x17

Batman's mechanic Harold is pictured riding in the Batmobile for the first time and goes on to become a supporting character. I consider this the 2nd "major" appearance of Norm's Batmobile Mk.III, while to my knowledge, it's the 3rd that's published.

1st major app. was in Batman #456 while #457 was minor (was also the 1st app. of Tim Drake's Robin costume). IMHO, in comparison to the many Batmobile designs, Mk.III is definitely one of the best iterations next to Dick Sprang's. At the beginning of Norm's fluid run, there were about 2-3 design choices in which he tested out that were short lived. But in Detective #601 the Mk.II made its debut with its vast similarities to the Lamborghini Countach. This served as the base design that would evolve into Mk.III that surpassed Norm's run into the Knightfall event up until its demise in Shadow of The Bat #30 when Jean Paul-Valley as AzBats booby trapped the car when Batman tries to use it. Later on, in Batman #515, the Batmobile goes back to the basics based on Sprang's modern 50's design with Kelley Jones pencilling the interiors.