These are the 4 variants of Cat 3054C engines, at one place!
Caterpillar 3054 Naturally Aspirated
This engine has a block where the starter goes through the block to connect to the flywheel housing.
Caterpillar 3054E
Cat 3054E engine has a ECU that controls the fuel pump. The Fuel pump is connected to the timing case.
Caterpillar 3054 Stress Block with Turbocharged
Engine with such specs are mostly used in farm tractors.
Caterpillar C4.4
There are 2 versions of Cat C4.4, that is acert and non acert. The Acert version is the newer version, it has 3 filters and requires after treatment. The Cat C4.4 engine is similar to Tier 4 Caterpillar C4.4.