Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

Having an LS swap was a dream for most people just a few years ago but now you too can have an LS swapped or upgraded car. Using some smart combos you can have the torque of the LS V8 for less than the cost of a set of wheels. The LS series engines come in many configurations and range from 4.8L up to 7.0L with the 5.7L LS1 being the most common swap choice.

Block and Heads:

Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

To start off you will need a good base motor to start with. The LS motors come in aluminum and iron block configurations. The iron block versions are available from most modern GM trucks and SUV's. The aluminum blocks come mostly in the car versions of the motor but there are a few select trucks and SUV's that feature them as well. For our purposes we are going to select the aluminum block to save weight.

The engine of choice for my build is coded the LM4. The engine features in stock form are below:

Displacement: 5.3L
Power: 290 hp (216 kW)
Torque: 325 lb·ft (441 N·m)
Compression: 9.5:1

Applications:
2004 Buick Rainier
2003–2004 Chevrolet SSR
2003–2004 Chevrolet TrailBlazer EXT
2004 GMC Envoy XL
2003–2004 Isuzu Ascender

The LM4 is basically the aluminum version of the 5.3L engine used in the GM Trucks and SUV's but most junkyards are not aware of the differences so they are priced in the same range. The current pricing in my area shows that I can pick on up for $500 with 119k miles.

Buying this motor from a junkyard will usually net you the engine assembly plus intake manifold, injectors, throttle body, and engine harness. Some junkyards also include the mass airflow sensor and ECM.Current Running Total: $500

Heads/Cam:

Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

The head and cam set on this motor is made for a heavy truck so it is biased towards torque. In order to extract some extra power, we are going to swap the heads and put in a more aggressive cam. The heads of choice will be 799 heads from the newer GM Truck. They are equivalent to the 243 LS2 head minus the sodium filled Valves. The current going rate for these heads on the used market is $250. We are going to add a GM LS1 hot cam to this combo as well as it provides a nice bump in power over the stock cam and can be found new online for $100 or less. Rounding out the package will be some LS2 Valve Springs and Retainers which run about $60 online. You can sell the factory head and cam package for about $80.

Current Running Total: $830

Top End:

Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

In most cases the engine swap will be going into a car, so you will need to remove the truck intake, injectors, fuel rail, and Drive-By-Wire Throttle Body. The top end set can usually be sold for about $50 on forums and eBay. You will need to purchase a car intake, cable throttle body, injectors and fuel rail to replace these parts. The average price for all of these pieces is about $150.

Current Running Total: $930

Front Drive:

Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

The truck accessories sit much further out than the car version so you will want to use car type accessories. The budget setup will be from the LS1 Camaro. The harmonic balancer can be picked up for about $50 new and the matching water pump can be found for about $60 new. The remaining required item will be the alternator which run about $40 used. The belts and tensioners that are needed will be another $50. Power Steering and A/C are not required so they are not included in this calculation.

Current Running Total: $1080

Ignition/Wiring:

Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

The recommended start for these applications is the truck starter which can be found in most GM V8 trucks built after 2000. This usually runs about $30 used and is built for two large bolts so it has less chances of cracking. The wiring harness that comes with the motor can be modified to eliminate items that are not used for the swap and then integrated with fuse box of your swap car or in this case we will build a small secondary fuse box. This usually runs about $50 in materials.

Current Running Total: $1160

Fueling:

Power for Pennies: Build a 400hp Chevy LS Motor for Under $1200

Supplying fuel to your engine is a big part of the equation and in most cases it can be solved simply with the use of a LS1 Corvette Filter/Regulator assembly. This can connect to the fuel rail using a simple fuel line or be adapted to a nice AN line. The other side can run to your tank to connect to an in-tank or in-line pump of choice. The Filter/Regulator assembly runs about $35 from WIX.

Current Running Total: $1195

Other Items:

The engine will come with truck headers and those may or may not be able to be used in your application so those were not considered here. The swapper will also choose the type of transmission and remaining fuel system they wish to build so those were not part of the consideration as well.

Conclusion.

This sample description will get you most of the way towards a great build for a fairly low cost. There will be other items to consider and many customizations based on the vehicle that it is being swapped into. The simple fact is that this will give you a healthy modern motor with plenty of horsepower and torque on tap.

See More from my series on LS Engines:

How to Score a 500hp LS Engine for FREE

My Latest Project. LS2 6.0L V8 Legacy GT RWD