Nice project. I believe that is a Toyota rear end. Check this web site it might help
http://www.off-road.com/trucks-4x4/tech/toyota-differential-identification-18588.html
I hope the title works out for you. I went through not having a title or vin on my car and I know the feeling. Here in California the don't make it easy to do it the right way so you pretty much have to cheat the system