Coach Joe: to me it does not look too far off 1/43. Remember that IRL that 53 Ford would have been shorter, more narrow, and higher than a Dodge Charger R/T as most modern cars moved in the direction of lower and longer in progress from the 50's. You could get the length of the actual car likely from the internet and compute the actual scale. P.S. thank goodness you didn't by a "Super Bird" Dodge or it would really look long (LOL).
Best Regards
Don