Where is your battery in trunk or engine compartment? What size cables are you running? You can run the biggest battery and high output alt you want but those cables make a huge difference.

My daily ride BB Suburban has always given that urgh urgh to start. From the factory the cables were rediculously small. THE CASING LOOKED LIKE IT WAS HIDING A 4 GAUGE WIRE!! I just today finished changing and adding additional grounds to #2 cable and ran a #4 cable for the grounds and alt to battery. I went from 13.8? to 14.7? at the battery. I was amazed. It now cranks like it has never done. I can turn on accys with almost no drop. Everything else is bone stock

For trunk mtd deals by some real heavy gauge stuff. Even better go to MAD electrics web site you will be enlightened 10x what I can offer. Cheaper than buying expensive batteries, high output this and that.



By the way if you want great source for wire try a marine store chain such as Marine West. They have cable there that is bigger that you will see in any auto parts store.