**71 Dart wont start after CAM, Timing Chain and HEAD Cylinder install** HELP

The easy way, after the rotor is reasonably close; is to just advance the timing as the engine is cranking, until it springs to life. If it kicks back, just retard it a smidge.
Your start-timing window while already cranking is huge; from about 5* retarded (with extra throttle opening), to about 25*advanced, or even a tad more. Huge I tell ya. And it will idle at those numbers too. But after it fires and runs, you can re-position the D to where ever it likes to be. Just don't go WOT, until you get it set more accurately.