The difference between LS3 and L99

[George-CZ]

How to determine the engine type if it is removed from the car?

The seller claims the LS3 but the engine is coupled with an automatic transmission.

How can I safely recognize LS3 from L99? ...at the first sight.

I know ... Pistons, cam, oil pump...
But it's inside the engine. maybe engine number.

But from the outside?

Simply first sight. Exist anything?

[JerTM]

Look at the engine valley cover. An LS3 is smooth, an L99 has what looks like circuits.

[SlingShot]

VIN

[hunter1660]

with the motor out of the car and no transmission attached the timing cover is the first thing thats visibly different as it is a little thinner and has the cam sensor on it. and the valley cover is noticeably different as well as it has wiring for the dod coming out of it where as the ls3 doesnt have dod. Per ls1 tech

[pnwdan]

Originally Posted by SlingShot

VIN

J is L99
W is LS3

[Rock-It Man]

Look at the VIN on the block.

J=L99
W=LS3

Also the VIN should match the car if the engine is original.

[christianchevell]

It would be in the VIN the easy way the eighth number/letter being W for ls3 or J for l99. Out side the car though.... heres a article on a VVT cam swap showing the valley cover and some of the internals. http://www.superchevy.com/how-to/eng...retaining-vvt/ I do believe the valley covers both have DOD friendly marks on them l99 or ls3.....I think you can look to the PCV system also for a difference between the two...and lifter baskets are different under the covers....


heres a pic of a l99 with autotrans;
https://www.ebay.com/itm/2014-Camaro...kAAOSwIDZbOkD6

if you look theres a PCV line on the back of the drivers side cylinder head coming off the block...….
this one shows it better; https://www.ebay.com/itm/Chevrolet-P...QAAOSwZ5hab16c











heres my ls3 minus that line you will notice the pcv vents differently, and I think serial numbers are up under the front passenger head on the block and the VIN is on the back drivers side where that PCV comes for the l99.,(think its a black cap on the ls3 not the PCV line). I am sure Elite engineering instructions for oil catch cans could tell you more. Good Luck. I would look for that line the easiest way to tell IMO. Valley covers up under the intake.

[JerTM]

The article Christian supplied shows a good look at an LS3 valley cover. It's flat on the top. This article shows a good look at an L99 valley cover. https://www.speartech.com/category_s/1822.htm

[saluki]

arent heads different? 821's vs 823's

[christianchevell]

Jertms article shows the difference in a couple other things like the timing cover from the Cam phaser…..

[nancygrl]

It could also have had a LS3 conversion done to it. Back in the 5th gen days it was quite a popular mod.

[pnwdan]

I'm going to put money on it being an L99. Most people not directly involved in the Camaro world have no idea the auto cars don't have an LS3. Heck I work with a guy that has had an 11 SS auto for 4 years and keeps telling me the previous owner made it an LS3 even though I remember him having his tuner tune out the DOD..

[George-CZ]

Thank you all for useful information.
VIN is probably the fastest and most effective way to distinguish motors.

Thanks all of them once again.