to install a fully automatic antenna you need a switched 12 volt constant output from the radio in the car. the factory 240z radio does not have this output. Therefore, the "switched" factory antenna is your best option. If you go to an aftermarket radio there will be an output for antenna (usually a blue wire) that will trigger a relay on a fully automatic antenna, but remember that you will have to do some additional modification to the wiring harness for a fully automatic antenna.
I just picked up a nissan competition rally transmission, fire system and ajustable front and rear swaybars, all for $300.00. life is good!..he has a torson gleason R-200 4.11 but doesn't want to sell it.....
I have what you need, I have a perfect gas tank that I had completely gone through and re-done. I have decided to go to a fuel cell instead. you can have it for what i have spent to have it re-done. -the tank was disassembled, cleaned out, recoated inside and powder coated black on the outside. If you interested you can e-mail me at gcarter@sd.znet.com thanks, Ron