Here's my method to install git on centos 6.
sudo yum groupinstall "Development Tools"
sudo yum install zlib-devel perl-ExtUtils-MakeMaker asciidoc xmlto openssl-devel curl-devel
sudo yum install wget
cd ~
wget -O git.zip https://github.com/git/git/archive/v2.7.2.zip
unzip git.zip
cd git-2.7.2
make configure
./configure --prefix=/usr/local
make all doc
sudo make install install-doc install-html