i went ahead and got another z. 
its a 75 280z.with an auto. its silver and the framerails are perfect! 
the only rust on the floor/rails i found was  on the passenger side floorboard where the rubber plug was. 
it also has the bottom of the driver's door all rusted out but i will be replacing the whole door. 
i plan on just driving this one on the weekend.(i have a company truck i take home all week   ) 
ok now im just ravin! 
im so happy.i sold my old z cause im trying to get into a house bui just couldnt resist. 
i havent been posting for a while but i've been reading in just about every day. 
thank god for this site!