Ah no not dissing your boat tail Jethro. I just need to keep it simpler for now. If later I want it longer I can extend it back.
Lots of newer cars have a big advantage in aero over these old vehicles. Square front, square roofline. Too bad that they didn't make the trunk about 6-8 inches taller.
I found a rabbit with smoke on this web site.
I combined the image it with the profile that I took of my car earlier today.
Came up with this:
I figure it the smoke wants to follow a certain line then my whaletail should be just about 2 bricks high just about where I have it positioned.