My K20 was a factory 6.2 till I swapped it out for the 454. The 6.2 had dual batteries. They were directly conected to each other. When I did the 454, I just put one battery back in there on the passenger side. When the truck was a diesel, with a battery on the drivers side too, I had my amp for my sub wired to that battery. Now, with the battery on the passenger side, the power cable for the amp won't reach and I have no boom boom. lol Anyways, my question is....(excuse my electrical ignorance) I want to install the other battery so I can rewire my amp...Can I wire the two batteries together like they were with the 6.2? Or do I need to get an isolator thingy? Both batteries are identicle, quality batteries and almost new. Alternator is a 140amp power master. This is my dd...no winch or lights or any other high draw stuff....The Sony 600 watt mono sub amp is about the only extra electrical thing I have.