* Vehicle: The 350 was used in many different Chevrolet vehicles (trucks, cars, etc.), each with different weights, aerodynamics, and transmissions. A light Camaro will get far better mileage than a heavy Suburban.
* Transmission: Automatic or manual, and the gear ratios within the transmission, significantly impact fuel economy.
* Axle Ratio: The final drive ratio in the rear axle affects how many engine revolutions are needed for a given road speed. Lower ratios generally mean better highway mileage, but poorer acceleration.
* Driving Style: Aggressive acceleration and high speeds drastically reduce fuel economy.
* Condition of the Engine: A well-maintained engine will be more efficient than one needing repairs.
While you might find *average* figures quoted for certain models online, these are broad estimates. You won't find a precise MPG for a generic "1974 Chevrolet 350 engine." To get a better estimate, you need to specify the *exact* vehicle it was in.
