it used to be very common to cut one of the normal on car compressor kinda like that and use but its common to break that bolt doing it.
Everyone would put a socket on the bolt under the compressor
this picture was found on ls1tech. the only issue my cars have had is a lack of money to do something the right way thus why Im not bothering to do anything right now.
Heres my ghetto fabolous Valve spring tool. I made this up a little over a year ago for changing valve springs. The steel plate tool was getting to be a real PITA.