Turn Key Engine Supply - Gen III 5.3L LS

With the constant onslaught of simple and reliable EFI horsepower available today, it's easy to forget that not all of us want or need huge power in a large package. Many truck projects on the road could benefit greatly from a more basic approach with a smaller cubic-inch assembly that would be a little lighter on the wallet. At the forefront of the Gen III and Gen IV LS engine rush is Turn Key Engine Supply located in Oceanside, California. For those wanting a smaller inch engine that still packs a decent punch, Turn Key has three engines just for you. With a range of 327ci 5.3L engines putting out 350, 400, and even 450 hp, we wanted to know more about these powerful and reliable engines.

Turn Key proprietor, Kolby Enger, has built a 14,000-square-foot empire of LS technology that can turn out an engine for a swap, sand car, rock crawler, race car, and everything in between. Turn Key's premise is to build its engines with top quality parts that will last, and give the customer nearly everything necessary for a successful installation and upgrade to GM's phenomenal LS power. According to Kolby, customers will only need to connect five wires, fuel, and cooling to be on their way to horsepower nirvana. With that kind of information in hand, we stopped by the company's headquarters for a closer look at what magic lies beneath a 400hp 5.3L.

1. Beginning with an aluminum block already prepared with cam bearings, a new 5.3L hydraulic roller camshaft from GM was lubricated and gently maneuvered into place.
1. Beginning with an aluminum block already prepared with cam bearings, a new 5.3L hydraul
2. Keeping the cam inside the block is a factory locking plate.
3. Main bearings from Clevite were installed and heavily lubricated in preparation for the crankshaft.
3. Main bearings from Clevite were installed and heavily lubricated in preparation for the

4. A stock, nodular iron, 3.62 stroke crankshaft was dropped into the bottom of the block.
5. With additional Clevite bearings installed, the main caps were prelubed, and set over the crankshaft with high-tensile fasteners from ARP. One point to note on the LS main caps, they bolt not only through the caps into the block, but also through the block sideways into the cap. This design ensures a rigid and sturdy mounting for the crankshaft, allowing it to be more structurally sound.
5. With additional Clevite bearings installed, the main caps were prelubed, and set over t
6. Factory bolts require a stretch gauge, as they are torque-to-yield, single use fasteners. ARP’s hardware, in contrast, can be used over and over requiring only a normal torque wrench to install.
6. Factory bolts require a stretch gauge, as they are torque-to-yield, single use fastener

7. With a key installed into the keyway, the crank sprocket for the timing set could be firmly seated.
7. With a key installed into the keyway, the crank sprocket for the timing set could be fi
8. After both gears were timed correctly, the heavy-duty LS7, single row timing chain cam sprocket was locked down.
8. After both gears were timed correctly, the heavy-duty LS7, single row timing chain cam
9. Oil is of great necessity to an engine, so Turn Key installs factory performance pumps commonly found on later engines.
9. Oil is of great necessity to an engine, so Turn Key installs factory performance pumps

10. All eight flat-top Mahle pistons and GM rods were assembled and ready to go on the workbench. Before sliding the pistons into the block, the cylinder bores were given a dose of oil and a piston ring compressor was used to allow the assemblies to be slipped down the barrels.
10. All eight flat-top Mahle pistons and GM rods were assembled and ready to go on the wor
11. Again, Clevite bearings were installed with heavy lubrication before the ARP hardware was tightened on the rod caps.
11. Again, Clevite bearings were installed with heavy lubrication before the ARP hardware
12. GM LS engines require alignment tools to position many of the covers since they serve a double purpose. Here, the front timing cover was installed with a new metal-based seal. It will later be finished as part of the oil pan.
12. GM LS engines require alignment tools to position many of the covers since they serve

13. All LS engines use a windage tray and this 5.3L’s got slipped onto its mounts before a fresh oil pickup tube got the go ahead.
13. All LS engines use a windage tray and this 5.3L’s got slipped onto its mounts before a
14. If you look closely, you can see where the front two bolts for the oil pan clamp to the cast-aluminum front cover and not the block. Without proper alignment of these parts, oil leaks would be rampant.
14. If you look closely, you can see where the front two bolts for the oil pan clamp to th
15. GM designed nearly every part on the LS to be an integral part of the engine and not just a simple cover. Here, the valley cover was being dropped into position between the cylinder banks.
15. GM designed nearly every part on the LS to be an integral part of the engine and not j

16. A new GM cam position sensor was also installed.
17. For those not familiar with the GM LS engines, these are lifter trays. The roller-tip lifters are encapsulated in the trays during disassembly and reassembly. The trays themselves set into a cavity above each cylinder bank in the block. You can see the flat sides in the tray bores where the lifters protrude. These serve to prevent the roller lifter from spinning in its bore.
17. For those not familiar with the GM LS engines, these are lifter trays. The roller-tip
18. Multilayer steel (MLS) cylinder head gaskets are used extensively in both factory and Turn Key’s builds.
18. Multilayer steel (MLS) cylinder head gaskets are used extensively in both factory and

20. Each fastener is marked as it reaches final torque value. With so many engines leaving Turn Key per year, it’s easy insurance to be able to tell at a glance the job was completed.
20. Each fastener is marked as it reaches final torque value. With so many engines leaving
21. Original pushrods from GM have been known to bend when abused. To remedy that, these engines are fit with 5/16-inch pushrods from Manley. They offer a much stouter tube size to put up with performance conditions.
21. Original pushrods from GM have been known to bend when abused. To remedy that, these e
22. Nothing more than the original steel 1.7-ratio rockers were necessary to achieve the horsepower goal safely. That’s something to be said since this whole engine hasn’t had much more than factory parts thrown at it.
22. Nothing more than the original steel 1.7-ratio rockers were necessary to achieve the h

23. Original valve covers were used with new gaskets to seal them up tight.
24. A pair of knock sensors were dropped into place in the valley cover and then sealed with GM rubber grommets. Check out the custom work covers over the intake ports so nobody drops anything into them. Quality assurance is job one.
24. A pair of knock sensors were dropped into place in the valley cover and then sealed wi
25. GM'S LS-series engines use vents to allow steam to escape across the heads. Here, the front tubes were being installed.
25. GM'S LS-series engines use vents to allow steam to escape across the heads. Here, the

26. Utilizing a locking tool on the rear of the crankshaft allowed the front crank pulley to be pressed on.
26. Utilizing a locking tool on the rear of the crankshaft allowed the front crank pulley
27. Keeping with the factory theme, new spark plugs from AC Delco were used to fire the cylinders.
27. Keeping with the factory theme, new spark plugs from AC Delco were used to fire the cy
28. Turn Key liked to use the F-body front accessory mounts, but the parts were discontinued. Undaunted, these killer billet mounts were designed to mount the alternator up tight to the block, out of the way.
28. Turn Key liked to use the F-body front accessory mounts, but the parts were discontinu

29. This additional mount is for the power steering and gets used dependent on the final destination for the engine.
29. This additional mount is for the power steering and gets used dependent on the final d
30. A CNC pulley is included for the power steering pump that overshadows the original equipment by far.
30. A CNC pulley is included for the power steering pump that overshadows the original equ
31. Gen III water pumps come with either a vertical or horizontal water port depending on whether the installation is intended for a truck, car, or custom. This engine was headed for a custom truck application so the horizontal port was chosen and bolted to the front of the 5.3L.
31. Gen III water pumps come with either a vertical or horizontal water port depending on

32. A trick billet port for the thermostat was included.
33. No serpentine belt system would be complete without a tensioner.
34. Original mounts and coils from GM ensure a smooth installation without adding headache for the end user. Turn Key’s harnesses plug right into the factory weatherpack connectors.
34. Original mounts and coils from GM ensure a smooth installation without adding headache

35. Intake manifolds can consist of a myriad of different choices. Most people wrongly believe the truck manifold doesn’t make power, but Turn Key uses them in all three horsepower configurations for truck owners wanting an upgraded engine.
35. Intake manifolds can consist of a myriad of different choices. Most people wrongly bel
36. One completed truck engine ready to be prerun on a dyno for break-in and testing before being sent off to the customer.
36. One completed truck engine ready to be prerun on a dyno for break-in and testing befor
37. Turn Key mounts all its engines in a test stand to run in the cam and check for noises, leaks, and anything other gremlins. Finding all was well, we headed for the dyno room for the moment of truth.
37. Turn Key mounts all its engines in a test stand to run in the cam and check for noises

Not only does Turn Key build the engines, it also offers fuel pumps, engine mounts, headers, harnesses, ECMs, and darn near anything else necessary to make your conversion to LS power go smoothly.