Light weight batteries?

Ya know what, I have a PC 680 Odessey that went dead after leaving the master on during maintenance on my airplane. It was flat, I recharged it, it's been sitting on a shelf for two years and it's still around 12.6 float.
Will check it tomorrow to verify that. I will try using it with jumper cables tomorrow to start the Dart, 418 small block. It's been sitting for 3 weeks. The starters between my plane and the Dart are pretty similar, I see no problem. The plane has a 360 cu in 4 cyl. Will let you know!. Would have to do some radical battery cable mods!