AC Spark Plug Service Manual
Dated October, 1968. 8-1/2" x 11", Black & White, heavily illustrated. Spark plug perfoprmance is the most important single factor in the maintenance of your Buick's engine. This shop manual covers AC spark plug design features (insulator, shell, resistors, seals, threads, reach), AC numbering system (prefixes and suffixes, thread size, heat range), AC heat range system (heat range, heat range chart, conversion chart), what your spark plugs can tell you about your engine, spark plug service (removal, cleaning, adjusting & testing, installation), radio frequency interference. One of the best manuals we have yet seen for complete information about the correct AC spark plug for your Buick. You'll want to keep a copy of this one in your tool box!