Zvezda M503
The Zvezda M503 is a maritime 7 bank, 42 cylinder diesel radial engine built in the 1970s by the Soviet Union. Its primary use was in Soviet missile boats that used three of these engines.
This engine may have had other applications, but due to its extreme weight, it would have been limited to ground or naval applications.
A German tractor pulling team designed a vehicle, named "Dragon Fire", around a methanol-fueled version of this engine; this modified engine is said to weigh including the gearbox, for use in the 4.5 ton tractor pulling class, making at 2,500 rpm.Comparable engines
