back when raising the back of the hood, and flipping the air filter lid upside down, were easy ways to get a small improvement in your et

 looks like 2 to 3 inch exhaust wasn't yet figured out.

But air intakes through the low beams? They were doing smart stuff!

http://www.overdrive.fi/forum/threads/vanhoja-valokuvia-ameriikan-raitilta.267070/page-1340#post-3527254