Another vote for inexpensive hardware store lacquer thinner. Spray with good ventilation, and preferably a good, half-mask respirator fitted with cartridges for Volatile Organic Compounds (VOC).
A very nice collection of muscle builds. The Camaro has some cool 70s toughness. I really dig the Challenger, and the colour is perfect. Got to get me some of that.
Nice work on the 0ld Chevy. The cap is very cool. Do any models exist with the correct C/10 badge? I'm wondering if the badge could be foil-cast from another model.
Nice work, Bill. I have a '73 442 project coming up (eventually), to be built from the JoHan '75 Cutlass, and have pondered how to do the hood vents. Your method looks good.