<VV> Valve Cover Racing?

[Frog Princezz]

Ok I know what valve cover racing is but I don't know the specs.  Can you direct me to a site or something?  Does the racer need to be a vair valve cover (don't we need those for our cars)? Are the wheels mounted under the cover or outside of the cover? Is it better to have a light racer or one very very closer to the 10lb limit?  I have made a few pinewood derby cars that have place very high on the track (second place) and first in design, I did a Grass Energy Pokemon car for my nephew (I mean he did it... yeah that's it) and his PT Cruiser that looked more like a Rolls Royce took first both on and off track and his Pick-up truck that looks just like my daily driver took third in design and fourth on track. Center weight worked the best if I remember correctly.  So is that true for valve cover racers?
 
I want a racer!!!! And maybe one day I'll race you guys and show you how it's done, right after you tell me how to build one!
 
Alesia
65 Monza Vert
Soon to be Valve Cover Dominatrix  = )