new battery/polarity issue

[sirshorty]

Hi I'm new to the forum and now have a 1971280sl.  do all SLs' need reversed polarity type batteries? Both my wires are black and the wire that is presently connected to negative terminal on the battery is grounded to the body. but it also looks like the battery is in the tray backwards.How can you tell if the car is positive or negative ground? The current battery has been slow draining and now cant take a charge so i need a new one. Any suggestions would be great. thanks
shorty

[scoot]

All SL's are negative ground.  I think is group 24 size but it might be group 24F or whatever it is that has the terminals reversed.  Search the forum, easy to find battery at any auto parts store.