Hello MIA, the chassis for the Ford is made with a .032″ brass sheet I gear it 33/12 with a Piranha 21,500 rpm motor it weights 92 grams the Porsche chassis is heavier since I used .064 Brass sheet its geared the same but with a 25,000 rpm Piranha motor it weights 108 grams.
The Porsche runs better so I think I am going to change the gear for the Ford to 32/12 for speed improvment.