In my opinion, the fusible links are the things most likely to be stressed and/or blow from hooking the battery up backwards. It might hurt the alternator too, but that won't prevent from starting. With today's gas, anything that sits more than 2 years is likely to have a failed fuel pump. Since checking that is easy, I'd recommend doing that 1st. I've seen a lot of failed fuel pumps lately, so I'm guessing that's it. Tim