Absolutely necessary
Not just a figure of speech, you absolutely NEED this tool to properly time a Ford 4.0L SOHC after any type disassembly involving the timing chains. Unlike Ford's Modular V8's, the cam shaft sprockets are not keyed to the cam and you need to loosen them to time the engine. The toolkit works very well, and if you know how to use it, it is almost impossible to screw up the cam timing.