Will a 1989 jeep Comache motor fit in 1994 Cherokee?

No, a 1989 Jeep Comanche engine will likely not fit directly into a 1994 Jeep Cherokee without significant modifications. While both are Jeep vehicles, the engine bays and mounting points changed over the years. Even if the engine *itself* were the same type (e.g., both are 4.0L straight-6), the accessories, mounts, and perhaps even the transmission would be incompatible. You'd be facing a major engine swap project requiring custom fabrication.