The LQ9 is great for an "all motor" engine. The LQ4 is perfect for boosting (twin turbo 1000hp for $5k-been done on hotrod). The main difference being the 9 has flat top pistons (higher compression too) and the 4 pistons are dished. Lots of Jeep guys use these engines. They are VERY SIMPLE to build, install, and get running.
Edit: A friend and I built up an LQ9 and installed it into his Jeep LJ. Other than measuring ten times before mounting the new motor mounts (measure 1000 times, cut once), it was a walk in the park. Everything is plug and play with these too (just like any LSx).
Edit: A friend and I built up an LQ9 and installed it into his Jeep LJ. Other than measuring ten times before mounting the new motor mounts (measure 1000 times, cut once), it was a walk in the park. Everything is plug and play with these too (just like any LSx).