I just bought a new cold start top post battery CCA 760 for my 2002 chevy blazer. Need to replace
negative battery cable. How do I start?

 

Negative is easy, it's usually a short one that goes straight to the block but I am not familiar with specifics on these vehicles. I think that you can also buy an adapter from post to GM style but I am not sure about that. Call NAPA and ask them.

 

better off just getting a Side post with screw-term style battery, but if you must -

The Negative cable goes to the block, frame, and core support. the positive cable goes to the Alternator, MEGA-Fuse,and starter, go with #0 Copper stranded wire for all wires, and you will have to effectively makeup a custom cable as i dont think anyone makes conversion cables, alternatively find a top post to screw terminal/sidepost adapter. you will also need to source a fuseable link for the Alternator. sized for whatever output of Alternator you have.

 

You got the wrong battery if it is top post Take it back for a side post Why would you change your truck to fit your battery?
Outside of that You will need to change both posts This would be a good time to upgrade the wire gauge to something thicker for future extra uses
You will need 1/0Awg wire (welding cable is strong and cheap) A hammer lug And lugs that fit the gauge of the wire, A hammer, A youtube video on how to use a hammer lug Top post battery clamps And a youtube video on how to install them If you get a different battery may i recommend a 78 series duel posting (top And side) CCA 800 battery Which you will need to remove the rad cap off to squeeze in the battery ( Yes that close of a fit) This is for that extra cold cranking power in winter And a whole extra cell of reserved power. If you do not have the mechanical background skill of doing a battery swap 2 or 3 times before hand You will need someone that has to understand the smaller connected wires to Or from the battery that also need to transfer to the clamps