look on the passenger side on the side of the engine block .
440 engine or the model 440 dodge?
the 440 engine had 375 horse.
All GTX's produced had the 440 engine.
These has 4 different marks
possible need carb rebuild, or a flat cam lobe . Could be timing or bad timing chain.
its a 75 to 79 440 out of a truck or motorhome.
The serial # and the date that the engine was made is on the side of the engine block by the freeze plugs on the passenger side of the engine., if you looking for the engine size it's stamped into the engine block behind the distriburetor on the block and if a 440 it's on a plate just above the waterpump.
base engine was the 383. optional was the 440 , 440 +6 (3 2bbl carbs) and the 426 hemi
any 440 takes premium gas.
The 440 was detuned to 280 hp in 72