Can you put a Chevy 350 bigblock in your 1998 Jeep Grand Cherokee?

No, you can't easily put a Chevy 350 big-block engine into a 1998 Jeep Grand Cherokee. The engine bay is simply too small. The big-block Chevy's dimensions are significantly larger than the space available, and there would be major interference with the firewall, suspension, and other components. It would require extensive, likely impossible, custom fabrication to even attempt it. The project would be incredibly difficult, expensive, and probably not worth the effort.