Volume Four of the Shop Dope series contains 160 pages of technical information, specifications, drawings and photographs on all 1957-69 models. Covers all Pan head, Shovel head, XL, XLCH, XLH and Servi-car, with several pages on Hummer, Model 165 and Super 10. This is the only publication that contains the specialized information on critical items such as Pan head brake drum conversions and Shovel head primary lubrication. Included are several sections covering the electrical system which highlight troubleshooting, generator conversion, and the electric start motor. A special feature of this manual is the service bulletin index which covers bulletins issued between 1947 and 1962.