Stage 5 Harbor Freight Predator With a Turbo and EFI Is the Final Boss of Go-Kart Engines

I’m at the point in my life where Harbor Freight Predators are more intriguing than LS engines. Obviously, they can’t hold a candle to GM’s budget performance darling, but you don’t see them swapped into every classic truck and hot rod (only the random Honda Insight or Chinese UTV). Then, you have folks like Red Beard’s Garage on YouTube who built a 670cc Predator, complete with a turbo, billet pistons and connecting rods, electronic fuel injection, and more. How could you not be hooked?

This fella does all kinds of work on small engines. You can watch him tool around with single-seater go-karts, like the Yerfdog Spiderbox—what a name—as well as modded pit bikes. But this V-twin build might be the most extreme project he’s taken on, in terms of real speed upgrades.

Quite a few aftermarket companies provide support for the 670cc Predator, so Red Beard’s Garage had plenty of parts to choose from. In addition to the turbo he bought off Amazon, which normally helps power Bobcat skid steers and Doosan forklifts, he’s running a big-name Holley Sniper EFI, plus …