Southern Performance Systems

Phone: 678-482-0866

Today's Muscle Engines for Yesterday's Cars

SPS is a Chevrolet Performance Authorized Reseller

LS Restomod Conversion Services

Thinking about putting some Modern Muscle into your Classic Muscle Car or Hot Rod?

Swapping LS and LT Engines into older classics - C10 Pickups and Muscle Cars of yesteryear is currently the hottest thing going on in the Hot Rod industry. With modern technology being combined with Classics, there are now 100s of components that make it all to easy to do LS/LT Swaps. So much can be done that you are only limited by your budget. When done right, swapping an old small block for a LS or LT engine will improve your performance, drive ability, mileage and most importantly Reliability. SPS can supply you with naturally aspired engines from 360HP to ground pounding Supercharged engines pushing 1,000 HP that can still be driven on the street everyday. Throw in a few brake and suspension upgrades and you got a classic that is reliable and dependable that you can drive anywhere. 

Note: Chevrolet Performance recently added a new generation of LT series engines to their lineup. This Engine still maintains the pushrod design of the LS series but has been upgraded with direct port injection.

Check out the Information below to learn more about what is involved in a LS conversion.


Engine options include LS1-LS2-LS3-LS7 in GM's Automotive Line and 5.3L-6.0L-L92-L9H for GM's Truck Line. The GM Performance Line offers the 480 & 525 Horse Power LS3s plus the LSx 376 and the LSx 454. Also available are the LSA and LS9 Supercharged engines. Horse power options for the factory and performance LS engines range from 300 to 665. SPS offers custom builds using aluminum block and the more serious LSx block. We have LS engines that make over 1,000 horse power when outfitted with a Supercharger. The new 8-Stack Fuel Injection systems are now available, as well as, the 8-Stack Cross Ram system. For the budget-minded, there are some good used take-out engine available at great prices.

Some New Engine choices for custom swaps are now available with the 6.2L LT1 naturally aspirated engine and 6.2L LT4 Supercharged engine. Also available is the new 5.3L L83 and 6.2L L86 truck series engines. All come with Direct Port Fuel Injection.

Also Available is the new LT5 6.2L supercharged engine making 755 Horsepower at 6,400 RPM. Powerful engines just keep getting better.

We take pride in our detailed and painted engines that can be customized per your request. We offer these engines with the color of your choice, chromed or polished components, polished or black anodized ARP bolt kits & much more. SPS is the only engine company that offers beautifully customized and painted LS engines. SPS is here to help matchyouto the correct engine for your needs.


Transmission options include 4L60E- 4L70E-4L80E-4L85E and the new 6L80E & 6L90E 6-speed automatic transmissions. SPS provides transmission that use a standard slip yoke, where as the production units use a fixed yoke that requires a 2- piece driveshaft. The 6-speed automatic can be used with a paddle shifter for those who want to shift the transmission without the use of a clutch. For high-horsepower engines, custom transmissions can be built to handle to extreme power and torque. Our stock torque converters work great with most engines and we have high-stall converters for our big cam engines. When setup correctly, these high-stall converters provide great gas mileage and work just fine on the highways. SPS will pair your engine and transmission with the converter that will work best for you.

With the Introduction of the new LT1 engine, GM now offers the new 8L90E 8 Speed automatic transmission.Plus the new 10L90E 10 speed automatic.

Manual Transmissions are available, including the Tremec TKO600 5-speed and T56 Magnum 6-speed. We will pair the correct clutch assembly with your engine that is best for its horse power rating. The T56 Magnums are installation friendly with multiple shifter locations available.

Engine/Transmission Installation Kits

When Retro-Fitting an LS or LT engine and transmission, SPS offers a large line of kits for Automatic and Manual transmissions. These kits include new mounts and brackets that replace the original parts. Each kit is made specifically for each model car and truck running LS or LT Engines. All kits are complete to install Engine and Transmission. Some vehicles may require tunnel modifactions.

Engine Control Modules & Harness Kits

All engine management harnesses are custom made to fit each engine/transmission package. Along with the harnesses that we offer, SPS also offers GM Factory ECMs (Engine Control Modules) and TCMs (Transmission Control Module) and custom programming. Each harness comes with Check Engine Light and Factory Diagnostic Plug which can be scanned by any shop with the right equipment. We also offer Holley ECM Controllers and harnesses for automatic or manual transmissions as well as FAST Electronics and Comp-U-Shift transmission controllers. Along with the LS engines harness, SPS now offers Harnesses and ECM Programming for the LT1 Line.

Header and Exhaust Systems

Most of the engines that SPS offers comes with factory exhaust manifolds. These will work fine if they fit between or inside your stock chassis. In most cases, custom headers will be required for clearance and are generally based on engine size, performance, and sound seeked. Custom Headers are available in full length tube and swept back tubes.


LS and LT Engines have different flow patterns then the older small blocks. A new design Double Pass Radiator is recommended for any LS swap. These come with single or dual electric fans. SPS offers these as direct bolt in unit. The radiators offered by SPS are all aluminum and made in the USA.

Air Intake Systems

LS and LT Engines are EFI systems that require a Mass Air Flow Meter to work properly. The MAF Meter is placed inline with an Intake Tube system that flows cold air into the intake. MAFs need to be positioned with about 6 inches worth of straight intake tube to each side of the sensor. It is recommended that Air Intake Systems for LS engines pull from a "cold" air source when possible, keeping away from the hotter air coming off of the radiator.

Serpentine Belt Systems

There are different styles of Front Runner Serpentine Drive Systems available for LS and LT series engines. GM offers several setups all designed for production vehicles. These work in a limited number of classic cars but most often the AC compressor tend to be an issue. SPS offers 3 different designs for the LS and LT engines. We offer the factory style look with AC compressor relocated or billet aluminum systems. These system will work with every application out there. Call us with questions for your vehicle.

Oil Pans

Both LS and LT engines stock oil pans will not work in for most applications due to the cross member and/or steering linkage. SPS offers custom aluminum oil pans that work in all applications. Our engine packages are sold with the correct oil pan that fits your vehicle.

Fuel Systems

LS and LT engines swaps require Fuel System upgrades with higher performance internal or external fuel pumps. SPS offers direct-fit fuel tank upgrades for many of the classic cars out there. While the LS engines require 58psi, it is important to remember that the LT engines need 72psi. From a standard in-tank system to a PWM (Pulse Width Modulated) system controlled by the ECM, SPS can help you design you prefect fuel system.

Steering Columns and Shifters

We offer Steering Column upgrades with tilt and provisions for column shift and GM designed cruise control. With these columns you can add Paddle Shift Controls on the column.

For Floor Shifter we offers upgrades for factory console designs. For Manual transmission we are able to provide shifters to match stock locations with most models.

Power Steering

SPS can upgrade your steering box from a 16:1 ratio to a quick steer box offering a 12:1 ratio. The 12:1 ratio gives you a lock to lock of 2.5 turns. We can also convert your car to a new rack and pinion with all new lines and fittings.

Air Conditioning

Southern Performance Systems offers Air Condition System upgrades for most cars and trucks using Vintage Air systems. We can upgrades your existing system or install A/C in your non-A/C vehicle. It will look like it was installed at the factory and provide excellent heat and cooling.

Gauge Clusters

The stock mechanical gauges in older vehicles will not work with LS or LT conversions. LS/LT Engines require gauges that are capable of receiving electronic signals from the ECMs. SPS offers Instrument cluster upgrades that fit in the existing dash and does not change the factory look or design. These gauges are available in an analog or digital design.

Brake System Upgrades

Swapping a more powerful engine under the hood means that upgrading your brakes is a big must. SPS offers Wilwood Disc Brake Conversion to help you out. In most cases Rotor size and the number of pistons per caliper is determined by rim diameter.

For Power assist brakes we offer hydraboost and vacuum diaphragm boosters. Hydraboost is recommended for higher performance engines running 12 ins or less of vacuum.


LS and LT conversions in older vehicles tend to change the weight ratio and alter the stance of the vehicle. This can have a drastic affect on the handling and stopping of the vehicle. The power of the engine, type of driving, and size/weight of a the vehicle should be taken into consideration when upgrading an existing suspension system.


We custom build driveshafts to length depending on the type of transmission that is used. Some of the newer transmissions have a fixed yoke and require a special splined driveshafts that "slips" in the middle.

Rear Ends

The older Classics came with tall gears for milage. Most came with singlepull axles as well. Some of the Performance Cars came with performance gearing and in some cases can be upgraded. With the Power output of the LS and LT Engines, new designed and engineered rear end gearing and axles are recommended in most cases. This will depend on horse power, type of transmission, and your driving habits.