Skip the auto shop - Our mechanics make house calls

Q: gas mileage difference 383 stroker motor 400 hp or ls3 computeried 400 hp same car

asked by on

I am wanting to get more power from my car but gas mileage is important.The gas mileage difference between the 2 engine choices mentioned

My car has 57000 miles.
My car has a manual transmission.

A: The gas mileage attained in either of these...

The gas mileage attained in either of these applications will depend heavily on your driving habits as you may already know. Either of these will also depend heavily on the type of intake system you are using to arrive at your 400 hp number.

When you say 383 stroker motor, I would assume you are speaking of an earlier generation 350 Chevrolet with the 400 c.i. crank and rods arriving at the 383 CI. Also, are we assuming both of these options would have the same intake manifold and fuel injection? As you may know this will also have a large impact on the type of camshaft, ignition timing, valves, etc. which will all affect fuel economy.

Since there are a lot of factors at play that determine horsepower and gas mileage numbers, it is very difficult to project which will do better in terms of fuel economy. However, the convenience and automatic adjustments that a computerized fuel injected motor offers are going to be much more accurate than a carbureted motor of the same horsepower.

Without knowing more detail, I would say from a big picture standpoint, the LS3 motor will do much better on fuel.

If you’d like a second opinion on this, have the car inspected by a certified technician, such as one from YourMechanic.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car was overheating almost to the red. I turned heater on, first it blew cold air then warm air for just a minute, then cold air.

Hi There, The heater not working may be related to the overheating problem you are also having due to a faulty heater blower motor or potentially a bad heater core. As you may know, the heater core is a small...

Q: blown engine

Unless there is a contributing factor in the failure, such as a deteriorated hose or hose clamp failure, the person who improperly connected the radiator hose is the only person responsible for repairing or replacing the engine. They may do...

Q: What Is Included in an Engine Inspection?

Engine inspections are an integral part of any engine repair or diagnostics visit. They can also be a separate visit to get a general condition of an engine, like in a pre-purchase inspection or a safety check inspection. The inspection...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.