Installing GIT from source - tooltwist/documentation GitHub Wiki
Steps are:
Download all gcc and other stuff
Download source and compile.
yum -y install zlib-devel openssl-devel cpio expat-devel gettext-devel gcc
cd /opt
wget http://git-core.googlecode.com/files/git-1.7.12.tar.gz
tar xvzf git-1.7.12.tar.gz
cd git-1.7.12
./configure
make
make install