I'd like to throw in my 2 cents worth; BEFORE you pull the spark plugs,use a compressor or air tank and blow gun and blow the loose crud away from the plugs. I loosen each plug about half a turn to loosen the debris,then go through and blow the caked oil and dirt away from the plugs,so it won't have a chance to fall into the cylinders when you remove the plugs. same goes for the built up junk around the lower edge of the valve cover,the carb,etc. It's all about keeping contaminants out of your newly acquired engine.
