Found this through google:
Chrysler's tank engine, combined five Chrysler six-cylinder, passenger-car engines on a single gear casing. It displaced 1,253 cubic inches, and put out
445 horsepower.
The 30-cylinder engine placed its No. 1 engine in a normal vertical position,
Nos. 2 and 5 at a 45-degree angle on either side of the vertical block and
Nos. 3 and 4 at slightly less than a 90-degree angle below vertical. Chrysler called it a "Multibank" engine, while the military officially called it the A-57.
The five engines were geared together and operated as a single unit. This was done by bolting a gear to the "clutch" end of each of the five crankshafts.
These five gears then meshed with and drove a center power unit "driven gear" which, in turn, propelled the tank. Each engine had its own carburetor, coil and distributor, and later moved from five to a single water pump.
Only one fuel pump, generator and starter was required.