Will a 1979 ford 5.4L engine fit into 1998 Ford F-150 4X4?

No, a 1979 Ford 5.4L engine will not fit into a 1998 Ford F-150 4x4 without significant and likely impractical modifications. While Ford used a 5.4L engine in later years, the 1979 version is a completely different engine family (likely a big block) with a very different design and dimensions compared to the modular 5.4L V8 used in the 1998 F-150. The differences in engine mounts, bellhousing pattern, accessories, and overall size would make it a massive undertaking. It's simply not a compatible swap.