YF3 is the Heavy Chevy RPO, black or white stripes available depending on color choice.
I saw this rusty floor '71 Heavy SB 12-Bolt Bench car advertised up here on Kijijij just last week, probably Canadian delivered so paperwork available if so...
http://www.kijiji.ca/v-classic-cars/oakv...gationFlag=true
[img]<<GRAEMLIN_URL>>/beers.gif[/img]
~ Pete