1950s Mack Holley Carburetor Spec Sheets

This set of Holley Carburetor Co. catalog sheets, copyright 1954, covers the carburetors fitted to Mack trucks, fire engines and buses. A contents page (Form MA-1) sorts them by engine: the AA-1 (R-389A) for the EY truck with the EN-354 engine, and the governed 885-JJS and 885-JJSG for the fire engine and LJ truck with the EN-707A and the C-41 bus (standard and maximum power) with the EN-672. It lists Holley and Mack part numbers, master repair kits and gasket kits.

Each sheet (Forms MA-405, MA-410 and MA-415) gives application data, a carburetor specification table covering the idle, main, power and accelerating pump systems, float level and settings, and governor spring, by-pass needle and governed engine speed, followed by engine tune-up data such as spark plug gap, breaker points, ignition timing and valve lash. Exploded views and indexed parts lists follow. MA-410 covers the superseded R-392A, R-393A and R-397A, and notes on MA-415 explain the economizer piston change described in Holley Service Bulletin No. 141. Restorers and mechanics can match a carburetor by part number and rebuild it to specification.

This 14-page copy is free to read online. Use the page box and thumbnails to move between sheets.