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