Mercedes Benz repair: 1978 450 SLC - Emissions: Vacuum leak?, vacuum leaks, vacuum problem

Question
We just purchased a 78 450SLC with 178k miles on it.  It failed the DEQ CO2 test by just over one point.  Any quick fixes?  
It appears we have at least one vacuum leak; possibly relating to the heater/defrost because the heater seems to only blow hot air.  Could fixing the leaks solve our problem?  What are some ways of checking for vacuum leaks?
One last question.  What is a good shop manual (NOT owner's manual, how much and where can we get one?

Thank you,

Nikki and Fred

Answer
Try having someone lean out the fuel micture at at the idle and see if it passes. You might also try to adjust the valves that might help. I know they are hydraulic but there is a lash adjustment when these cars get old. This might help your vacuum problem.