GM's engines? Like what is the difference between and LS1 and an LS2? LS6 and LS7? LT1 and LT4? I'd love to know! Never been told the difference!

 

LS1 350 in the C5 Corvettes. It is a new design, different from the old small blocks of 1955 to 1991.

LS4 454 in passenger cars. This engine had oval port iron heads, iron intake, Quadrajet carb, hydraulic lifter cam, and low compression. It made a lot of torque.

LS5 454 in 1970-1972 Corvettes, rated at 390 hp in gross hp in 1970, 365 hp in '71, and 270 hp SAE Net in '72. This engine had oval port iron heads, Quadrajet carb, hydraulic lifter cam, and low compression. It made a lot of torque.

LS6 This is a big block motor with tons of power. Also used in Chevelles and other muscle cars. This 454 was only available in '71 in Corvettes as a 425 hp version with aluminum heads. (bj) The engine had rectangular port aluminum heads, aluminum intake, Holley carb, solid lifter cam, and high compression.
LS7 454 crate motor that was never released in a production car. It was on the option list of 1970 as a 460 hp 454. The engine had rectangular port aluminum heads, aluminum intake, Holley carb, solid lifter cam, and high compression.

LT-1 Commonly called second-generation small block Chevrolet V8. (Reality is that several design generations of SBC existed prior to the LT-1.) To add to the confusion, the LT1 designation was also used in '70 on a motor. It features a new block design with 350 cu.in., overhead valve motor (i.e. cam in block, pushrods, etc.), reverse-flow coolant design (coolant to heads first), improved water pump design, improved ignition system, other small improvements as well. Obviously it bears little in common with the first LT1 motor (first gen block, iron heads). This LT1 was also a monster motor in its day! The second generation LT-1 was the standard engine in 1992 to 1995 Corvettes and the engine for automatic transmission cars in 1996. (bj)

LT1 The first generation LT1 was the 370 hp small block of 1970, featuring a high rise aluminum intake, a Holley carb, high lift camshaft, special heads, and high compression.

The second generation LT1 was the standard engine in 1992 to 1995 Corvettes and the engine for automatic transmission cars in 1996.

LT-4 The successor to the LT-1. Not sure of all the improvements, but hp is 340hp (LT-1 in Corvette trim is 300hp, 275hp in Camaros). Only available with the 6 speed in the '96 Corvette. (bj)

LT-5 The ZR-1 motor, built by Mercury Marine. 350 cubic inches, 4 cams, 4 valves per cylinder, etc. Originally 375hp, moved to 405 in 92 (?)(bj)

L36 390 hp version of 427, used 1966 - 1969

L46 350 hp version of the 327 from 1965-1968.

L48 Base engine in Corvettes from 1972-1979. While most feel it is a dog, it had average performance and was still a basic small block Chevy, so much could be done to enhance its performance. Basically, it was a standard 350, 8.5:1 compression, dished pistons, low performance cam, low performance heads.

L68 400 hp version of 427 in Corvettes from 1967 to 1969. This was basically the 390 hp 427 with a Tri Power on top.

L71 435 hp version of 427 from 1967-1969. The L71 used three 2 bbl Holley carbs on a low rise (almost flat) manifold with a triangular shaped air cleaner.

L72 425 hp version of 427 in 1966. This was originally rated at 460 early in the year and changed to 425 hp.

L75 300 hp version of 327 in 1963 to 1965 with a hydraulic cam.

L76 340 hp version of 327 in 1963, 365 hp version in 1964 and 1965. These had solid lifter cams.

L78 425 hp version of the 396 used in 1965 Corvettes.

L79 350 hp version of the 327 from 1965 to 1968 with a hydraulic cam.

L82: The performance 350" motor used in the 70s up 'til '81. Iron heads, various HP ranges up to 235hp, good cam (even by aftermarket standards). the L82 had a 4 bolt main block, forged flattop pistons, a good cam, and wide power range from about 2000 rpm to 5500 rpm. (bj)

L83 The L83 is the base, and only engine, in the '82 and '84 Corvettes.

L84 The fuel injection engine in the Sting Ray.

L88 Listed as a 430 hp 427, this was the factory race engine from 1967-1969. It featured aluminum heads, 12.5:1 compression, a single Holley on a high rise manifold, a special hood required to clear the additional height, and a list of required options. The 430 hp rating as at 4000 rpm so as to appease the insurance companies and to steer clear those customers who simply bought the highest horsepower without any knowledge of what the engine or car was. This was intended strictly for competition and was derated to avoid problems with pseudo racers of the street. With this option, the radio and heater were deleted.

L89 An aluminum head option on the L71 435 hp engine from 1967-1969. Correctly, it is the L71-L89 engine.

L98: engine used from 86 until the LT-1 came out (about '91?). This is the "old" small block design (first gen) with some mods (such as the one piece rear main seal). L98 also refers to the Corvette aluminum cylinder heads. This engine used electronic Tuned Port Injection. (bj)

 

WOW, thanks! I'm gonna book mark this ****! Doesn't the new C6 have an LS7 in it?

 

Here's are some very basic points to get the thread started. All of the engines you mention, depending on the application (Camaro/Firebird, Corvette, truck, etc), probably have different specification for cam, pistons, etc.

The LT1 is a variation of the traditional Chevy small block. It uses reverse-flow cooling, where coolant goes to the heads first, then to the block, which is backwards from the original Chevy small block.

LT4: Basically same as the LT1 with better flowing heads. Not sure if there were any other differences internally (cam, pistons, etc.).

LS1 vs. LS2: The LS2 is a 6.0L block in the C6 whereas the LS1 is a 5.7 using the C5. I'm sure there are internal differences, but I'm not up to speed on that.

LS6 has the same displacement as the LS1 (5.7L) but has some internal differences to improve the pumping efficiency of the motor. LS6 engine also have different heads and a better flowing composite intake.

LS7, I believe, is the 7.0L engine that is going to be using in the upcoming C6 Z06.

 

Got another question... if a car has low compression which means more torque, does that mean a car with high compression puts out more HP but less torque?

 

So, the new C6 has a 6.0L LS2 and the New Z06 has a 7.0L LS7?

 

The second generation LS2 in the new C6 is an all alumiminum design very similar to the LS1 in the C5. The new LS2 is 400hp/400lb.ft. torque.

The new LS7 in the soon to be announced Z06 is said to be 500HP/475 lb.ft. torque. It is also all aluminum and supposedly will have a dry sump oil system. We will all have confirmation of these facts on 1/10.

 

High/low compression has nothing to do with more torque vs. more horsepower. The volume of the cylinder before divided by the volume at the time the fuel explodes is called the compression ratio. In other words, it just "squeezes" the same amount of fuel into a smaller space.

A high compression engine wiill put out more horsepower AND more torque, all other things being equal. It requires higher octane fuel to operate without pinging.

 

ok this stuff just gets confusing sometimes...