6 volt systems need DOUBLE OTT (00) cable! Anything less and you are wasting your time. Until you have the proper cables in place, nothing else matters. And don't use dielectric grease on the connections, use vaseline or specialty electric goop for good connections. Add a ground from firewall to engine. Main ground strap should go straight to the starter bolt. If you guys want radios and the like then go 12 volt by all means. But if you just want your truck to start well and have bright lights, etc, then keep the 6volts and do it up right. Headlight relays are a good idea as well. thye are available in 6 and 12 volts. And if your taillights are weak, run individual grounds from each one to the frame. (Oh, and if you're putting 8volt batteries in 6 volt sytems, :mad: )