I stumbled upon something that I have not heard anyone else doing and
may be useful to someone somewhere. I have been having a heck of a time
getting my 356 running right after going to 1776 P&Cs. It got so bad I could
barely start it.  I suspected fouled plugs but since it is such a pain to
change plugs in this car I wanted to have some quantitative proof.
     I just happened to have an old, excessed Biddle Meggar ( similar to
http://www.jmtest.com/pages/productdetail.asp?ID=112 ) used to test
insulation in buried cable. You work the crank to generate 500 volts at the
test leads and the instrument converts any leakage current to a resistance
readings. A regular ohm meter only produces a tiny voltage and will not work
in this application.
     I hooked one lead to the engine case, the other to a spark plug wire.
Sure enough, all four plugs were showing less than a meg of resistance. New
plugs showed infinite. Now she fires right up but, still needs work on the
Webers. But that's another story.
Ken Lewis
http://neksiwel.20m.com/
in statu viae