Just a comment by Ron Ayers regarding the drag contribution of skin friction on the JCB car. He said that over 70% of the total drag at over 300 mph was contributed to skin friction. So things like fit, finish, body joint design and skin stiffness, which is especially critical on cars with flat sides or top, have a huge affect on the aero ability of any streamliner. Most top fuel bodies are made from .050 mag sheet and if you watch them at speed they are vibrating in and out at such a frequency and magnitude that there is no possible chance that they have attached air flow and attached flow, either laminar or turbulent is what you must have to be aero. If you look at the skins and inter support work on Marlo's liner you can see that Jim recognized this and provided a lot of support to prevent any skin deflections, I also think that he used .071 and thicker aluminum for skins which all help. (it also allowed him to really make the skins smooth and fit well by lots of filing with the "hungry file")
Rex