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How To Identify All Those Different Late-Model GM V8 Engines

Hunting The LS

By , Photography by Chevrolet Performance, GM, ,

GM CRATE ENGINE LIST
Description PN Source Price
LS327, 5.3L, 327 hp 19244096 Summit Racing $4,891.95
LS3, 6.2L, 430 hp 19258770 Summit Racing 6,995.95
LS3 EROD, 430 hp 19257230 Summit Racing 7,839.95
LS376, 6.2L, 525 hp 19259233 Summit Racing 7,899.95
LS7, 7.0L, 505 hp 19244098 Summit Racing 14,099.95
LS9, 6.2L, 638 hp 19244099 Summit Racing 22,516.95
LS3 / 4L65E combo CPSLS34L65E Jeg’s 10,719.99

10. One of the best-known differences among LS engines is with cylinder heads. Most passenger-car and many truck engines came with what are called cathedral intake ports, so called for their peaked-roof configuration.

11. Within a few years, the Corvette and later Camaro LS3 engines began using rectangle-port heads equipped with monster 2.165-inch intake valves. These larger heads can only be used on 4.00-inch-or-larger bore diameters.

12. GM has also changed fuel injectors over the past 15 years. The original tall-injector design with a Minitimer connector (not shown) was used on the LS1/LS6 and truck engines. With the LS2, the height remained but the connector changed to a USCAR style (left). LS7/L76/L92 injectors became shorter but used the same USCAR connector (right). With each of these styles come multiple fuel-flow rates ranging from 24 to nearly 70 lb/hr.

13. The 427ci (7.0L) LS7 is distinctive for several reasons. Its cylinder heads feature a unique intake bolt pattern, and while the intake rocker arms are offset like an LS3 or L92, the rocker ratio increased from the stock 1.7:1 to 1.8:1. The LS7 also uses a different aluminum block with larger bores and longer cylinder sleeves to accommodate its longer stroke.

14. Roughly around 2004, GM changed from using two different-length head bolts to making them all the same length. The change occurred with later cylinder blocks placing all threads deeper in the block.

15. There is an entire story waiting to be written just on the various LS accessory drives. Among the popular LS engines, there are at least six configurations with the truck systems (shown here), Corvette systems, the new ’10 Camaro LS3 configuration, the original LS1 Camaro version, and the separate drive systems for the new CTS-V and Corvette supercharged engines.

16. Another new branch on the LS engine tree is the variable valve timing (VVT) L99 engines, as used in the 2011 Camaro. The system employs high-pressure hydraulic circuits to advance and retard the cam timing to enhance both power and emissions. The L99 also incorporates active fuel management (AFM—formally known as DOD or displacement on demand). AFM drops four cylinders by deactivating the fuel injectors and the lifters so the valves don’t open. This is done to enhance highway-cruise fuel mileage.

17. If a new GM crate engine better fits your plans, Chevrolet Performance has a slew of options, including the 5.3 and 6.0L EROD engines as well as a new system called Connect and Cruise. This packages an LS3 with a new GM 4L65E transmission, converter and flywheel kit, engine and trans controllers, and an electronic throttle pedal. All you do is plug everything in, and it’s ready to go. The LS3 system is PN CPSLS34L65E. The price is steep, but literally all you do is connect and cruise.

18. Just as this story was going to press, GM released preliminary photos of the new LT1 Gen V small-block that will be used in the 2014 Corvette. The 450hp engine is a 6.2L, with direct injection being the biggest change. The basic LS architecture remains the same but with taller intake ports and high-pressure injection nozzles directed into the combustion chamber. Other details include VVT and 11.5:1 compression.

SOURCES
Scoggin-Dickey Parts Center
5901 Spur 327
Lubbock
TX  79424
800-456-0211
http://www.sdparts.com
Chevrolet Performance
800-450-4150
http://www.chevroletperformance.
com
JEGS
101 JEGS Place
Delaware
OH  43015
800-345-4545
http://www.jegs.com
Summit Racing
Akron
OH
800-230-3030
330-630-0240
http://www.summitracing.com/
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