What should I expect from the Jeep 258 Inline 6 engine?

I just bought a 1981 Jeep CJ5 with a 4.2L 258 straight 6 engine and a 4-speed manual transmission. This is my first time owning this type of engine. Previously, I’ve had a 4.0L in a Cherokee (loved it), a 2.5L in a Wrangler (wasn’t a fan), and a 304 V8 in a 1973 CJ5 (really liked it).

Now, with this carbureted 258 engine, I’m curious about what I can expect from this stock setup. The Jeep has 69,000 original miles, starts easily, and runs smoothly. It feels lively on the road too. I plan to use it for recreation—weekends, camping, and light off-roading, but nothing extreme.

Any tips, experiences, or information—whether positive or negative—would be greatly appreciated.

Your 1981 Jeep CJ5 with the 4.2L 258 straight-six is reliable and torquey. Expect decent performance for recreation, but maintain the carburetor and ignition system for optimal smoothness and power. Enjoy!

The engine generally produces around 110-120 horsepower and 195-220 lb-ft of torque. While it’s not a high-performance engine by modern standards, it provides ample low-end torque, which is beneficial for off-roading and towing.