318 Engine Build - A Parts Book 400HP 318

Adding a nitrous kit is the...        read full caption Adding a nitrous kit is the quick way to make a small-block run like a big-block. We bolted on a Nitrous Works kit in a few minutes just to punish our little 318.

The kit we selected was adjustable...        read full caption The kit we selected was adjustable for output by changing jets. Due to the hypereutectic pistons, we limited our boost to a 100hp shot. Don't get carried away with jetting. Follow the manufacturer's jet and fuel pressure recommendations exactly.

With a nitrous assist, our...        read full caption With a nitrous assist, our 318 was a genuine 500hp engine, pulling big power to our self-imposed redline of 6,400 rpm.

Power Squeeze
While 400 hp from a bolt-together 318 may seem like plenty, we figured with a little go-fast gas our little engine could go hunting for some big-block game. With the hypereutectic KB pistons, we decided to keep the nitrous moderate and sane, just enough juice to stalk some of the hardier street beasts we may encounter. Be aware that KB has very specific ring end gap requirements for nitrous use, and these must be followed during the build if any kind of life expectancy is to be had from the engine with nitrous. We selected a Nitrous Works jet-metered plate system, a quick and easy addition to any engine. The plan was to add 100 hp to our normally aspirated output, not an excessive amount, but enough to really notice.

The Nitrous Works recommended jets for a hundred horse shot were installed. installing the plate system was only a matter of unbolting the carb, slipping the nitrous plate between it and the manifold, and then running the fuel and nitrous lines to their respective solenoids. The solenoids were wired to a remote switch, and we were good to go. With an aim towards being conservative, the fuel supply was switched to 100 octane, and the MSD ignition was set to provide 8 degrees of retard upon the activation of the nitrous system. Adding nitrous at a low rpm can lead to excessive cylinder pressure, so we planned on hitting the nitrous at 4,700 rpm, which would equate to just out of the hole on the dragstrip and above the shift recovery rpm going down the track. The nitrous system delivered on its promise, boosting output to just above the 500hp mark, and maintaining a flat power curve up to our self-imposed redline of 6,400 rpm.