including General Motors' notorious LS engine line, most modern vehicles feature SOHC or DOHC engines. But what does that mean, and what's the difference between the two? First of all, SOHC stands ...

but they're not really able to run at high engine speeds like SOHC or DOHC motors. Here's how an overhead valve engine works, according to Cars.com: [T]he valves, which open and close to let the ...