For mild street engines, stock valve springs are more than adequate. But if you've screwed in a big bumpstick for strip-banging or banzai runnin', then pay attention. Our plan was simple: Install a ...

In this transitional period between the gasoline and electric ages, there's still plenty of room, and plenty of motivation, for last-gasp improvements to the combustion engine – and a Swiss R&D ...

Fittings such as these, for connecting a compressed air line to the spark plug hole for valve support, are available at most auto parts stores. Occasionally it is necessary or desirable to inspect or ...