The ignition switch uses a ground in the transmission to energize the starter solenoid. If it starts fine in neutral, but not in Park you have maybe a couple of problems. If neutral energizes the pull in solenoid, the ballast resistor may be no good. Jump across it to check it. The neutral switch may not be switched properly by the valve body detent, so it is internal. Eventually, it should be fixed for safety. The connector can be pinched for repairs to that.
Now you have changed plenty of the normal secondarty ignition components, so the primary(coil control) may have a problem. You need 12 volts at coil in start and in run. Their is a difference in both key positions but with the key on, there should be 12 volts at coil positive. If no coil voltage at positive, you may have a ballasr resistor, or fuse link or just a problem with the wiring. If you have 12 volts with key on at positive coil terminal, it may be a ECU, Spark Control Computer, Distributer Pulse from the wheel, or the related wiring. Some Federal 360's had each, California built were far in advance of the rest. I used to jump 12 volts from the battery to the coil positive to check em first. My 80 was not California and used a ballast resistor for the positive primary cicuit on the coil and a square ECU on the firewall for the negative side using the distributer to give it a pulse. Maybe the coil is bad, or the distributor is not turning. The ballast resistor is white and on the firewall. OK Joe
Friday, October 9th, 2009 AT 10:05 PM