[H. L. Chauvin]

FWIW: Sometimes we all become obsessed with technicalities, precision, and whatnot & often ignore some of the most simple items that are overlooked.

"If" this engine ran and stumbled along with too much gas, (i.e., too rich a fuel mixture), and "if" you now have black foul plugs which are loaded with carbon, later substituting a perfect carburetor and a perfect distributor will not allow this engine to run smoothly & properly without first cleaning these plugs "if" loaded with carbon.