New member advice please SL classic

[andand]

Hi All
Pretty new to all this forum stuff but wanted to ask about 1970's and 1980's SL280 or SL350 classic merc
I am looking to buy an old one either 1970's or 1980's I find that the 70's ones seem cheaper is there any reason for this?
Any help or advice would be great.
Cheers

 

[automaniaman]

Rust...

 

[rifiki]

in the bulkhead/fire wall.