I just got a late 70's blazer and it has a 350 with a 4 speed in the floor. Everything is their in the engine bay but it will not turn over at all. Or do anything when I turn the key. I have a hot battery on it. I dont know what is going on.

 

I would assume bad battery or loose/corroded battery terminals or cables.

 

first check battery connections. Do you have power in the cab? Check if your battery is good, is it sulfated? Is it charged? how old is it? next check the battery to ground. Then started fallowing connections and seeing if you have any frayed or shorted wires going to the the starting selanoid. Also check to see if you have good connection through the selanoid. Check to see if the starter has a good ground, corrosion will build up behind the plate the starter mounts too and thats the ground to engine. If your mechanic savy you can even take apart the starter and check the armeture and brushes. They sell rebuild kits for most starters for like $20. 80% of starters aren't bad they just have connection issues, it's just when people change them they make the connections better and say yep bad starter.