LSx Engine Identification
 

Here is a nice chart to help decipher the LSx engine designations:

Attachment 617898
Attachment 617899

Modified, updated from Source: Southern Performance systems

Significant Gen III Engineering Points:

1. All Gen III truck engines use iron blocks. Only the Camaro (F-Car) and Corvette (Y-car)LS1/LS6 engines feature aluminum blocks.

2. All Gen III engines have aluminum heads except for the '99 LQ4 engines that were equipped with iron heads. These engines received aluminum heads for the 2000 model year.

3. All Gen III engines share common main,rod,and cam-bearing journal diameters for ease of interchange. All blocks use a cross-bolted six-bolt main cap.

4. All Gen III engines are completely metric.

5. All valvetrain pieces are completely interchangable. The standard rocker ratio for all Gen III engines is 1.7:1.

6.All Gen III truck engines use cast aluminum oil pans that are deeper than the camaro or corvette pans.

7. All intake manifolds interchange. The truck intakes are roughly 3-4 inches taller than the passenger-car intakes.

8. All Gen III engines employ reusable gaskets for sealing surfaces except for the head gaskets. This makes it much quicker and easier to service the engine.

9. There are only two intake valve sizes for all the Gen III engines. Exhaust valves are all the same diameter.

10. Truck and camaro engines use cable throttle linkage while the corvettes use an electronic throttle. There are also some SUV engines with traction control that use electronic throttle control.

11. Bellhousing patterns are the same for all Gen III engines. The crank flange is basically the same depth as the bellhousing flange.

12. The Gen III firing order has been revised from 1-8-4-3-6-5-7-2 to 1-8-7-2-6-5-4-3. Note that the pairings 1-8, 4-3, 6-5, 7-2 remain the same, but the pairing order is different for reduced vibration.

13. The valve angle on all Gen III engines is 15 degrees versus 23 degrees for the origional and Gen II small-blocks.

14. The Gen III bore spacing is the same as the origional small-block, but each cylinder is ringed with only four head bolts instead of five.
__________________

Custom Cubes:
If you are fortunate enough to get your hands on an LQ4 6.0L engine block, you can bore it .030-over and purchase a 4.250 Lunati stroker crankshaft to produce a 434ci. GenIII engine.

Add a set of GM Performance Parts ZO6 cyclinder heads (PN 12560801) or have the stock LS1 heads ported and you've got yourself a serious engine.
__________________

All information is taken from Chevy High Performance Magazine May 2002 editio

Hmmm, I thought my '03 base Corvette engine was designated "LS-1" and rated 350/350...

Handy. :)

Sticky..:judge:

Thanks, added it.

here here :nod:

where is the LR4?

Man, they do come in many flavors!

I've edited my master list.
LR4 (All iron 4.8) full size trucks
LM4 (all aluminum 5.3 Trailblazer)

Thanks all!

Is there any way to identify an engine that is out of the vehicle? Any casting numbers or numbers stamped anywhere?

I have the same exact question, I supposedly bought a LQ9 but I bet it is an LQ4, I would like to know for sure. I checked in google with the numbers on the block and got no difinitive answer to my question. Anybody?

On the LQ4/9 engine, pull a plug, rotate a cylinder to TDC and look at the top of the piston. ( a bore-light for cleaning guns works great)

LQ4 is dished

Attachment 617803

LQ9 is flat

Attachment 617804

thats awsome Thank you.

How do I tell which one I have? I have a complete pull out with everything still on it. Would like to know without taking a lot off. Looking to put it in like it is.

Also need to identify the transmission. How to tell 4L60e to the 4L65E?

Is there numbers on the PCM or anywhere else to identify engine and transmission?

Very helpful info!!

Thanks!!

I think the trucks switched to drive by wire in 04' or 05', my 2005 2500HD 6.0L is drive by wire.

i have a 2003 4.8 that came dbw fyi soo.....
also if anybody is trying to tell the difference between 4.8s and 5.3s quick and easy, the stock headgaskets have either marked(4.8 or 5.3) on a lil tab that protrudes out
(im sure that will make somebody's life easier )

heres a decent pic of what im talking about
if you look hard enough you can see the 4.8 scribed into it

Attachment 278525

Thats awesome i have like 3 engines i need to identify 4.8 or 5.3... never noticed the tab...

PhilnTX there were several truck 5.3's that were aluminum blocks too