I just installed a Lokar neutral safety switch this past week. It was a neutral safety switch and backup light relay setup. We didn't use the backup relay though. Their instructions were bad though,had to call them twice for more info. on the installation. If you get a lokar give me an email and I will direct you thru the hookup.

https://sites.google.com/site/bluejaygarage/home
53 half ton http://s159.photobucket.com/user/sworden73/library/?sort=3&start=all&page=1
72 Nova SS sold
75 Corvette
52 Chevy Styleline Coupe