I didnt put enough antifreeze in it and it cracked between 2 freeze plugs.. How would i go about welding that up?

 

Do a search on Lock and Stitch method. Sometimes it works, and sometimes it does not.

 

Might be a lot of work to get to it, but you'd want to drill a small hole at each end of the crack to stop it from running. Next, you should try to grind a V in the crack to get some penetration. Then weld it up with nickel. I like tig process, but experienced welders can do it with ni-rod and a buzz box. Try to get the weld area as clean and warm as possible for best results.