While the Small Block Chevy may be the most tunable and the Chrysler HEMI the most powerful, Ford’s Flathead V8 engine has been around for nearly a century and is the grandfather of every V8 ...

This 5.0-liter straight-6 flathead engine could be tuned ... as it was built for economy models, Chrysler’s Slant Six engine produced good low-end torque and was found in many large models.