I gave back 7 and will now use # 19 on my Porsche 917. Double win as F1 gets 7 and I end up with number 19 and 20 for my entries.
Strange coincidence that I just happened to be putting the Avant chassis under the 917, and had a Cobra on the bench with a new Lego Technics chassis with a Piranha. All I had to do was vacuum form a roof for the Cobra. Both cars are now finished!!!!! Lots of time for testing until the end of September.