Ranger dies when i try to start it
 

I have a 2005 Ranger I am trying to get running. I bought the truck as a mechanic special so I have no background of the truck whatsoever. It has a 3.0 with a M/T and is 2wd and has about 160k miles. The truck was partially disassembled when I got it (down to the upper intake as it has a blown head gasket). I got it put back together to see what I was dealing with and if it would even start. Everything seemed to be working as it should, dome lights, headlights and all other electrical components. The Fuel pump and all dash lights came on when I turned the key to acc, but as soon as I turned the key to start it, the truck completely died. I disconnected the battery and after sometime, reconnected it and everything was working again. It has a brand new battery and terminal connectors. I made sure everything was tightened down and tried to start it again but the same thing happened. Once power was restored. I pulled the cartridge fuse for the starter and i was able to turn the key all the way without it dying, but obviously it wouldn't start. I went ahead and replaced the starter, but again, no luck. I checked the voltage with a multi meter, when touched to the posts on the battery it reads 12.9 +/- some, but as soon as I move the probe off the positive post to the terminal connector voltage drops to 1. something. That's about as far as I've gotten and am pretty stumped and was hoping to see if any of you could offer any help. Thanks.

That tells me the connection is bad or the terminal is no good.

I thought I had triple checked the terminals, but sure enough there was paint keeping from making a good connection, thank you.