The classic Ecto I was a 1959 Caddy ambulance, that as altered slightly in the sequel. In the recent reboot, the Ecto III was introduced, an updated 1961 or '62 Caddy, with red highlights. Let us suppose Big Daddy Roth (who is appropriatedly dead) designed the hot rod verson, the Ecto IV.

I drew this while suspended in time in St. Joe's hospital, last week.