GM engine question

[Falcon_LS]

I'm having a bit of difficulty "identifying" the engine in my Avalanche. The engine code in the VIN is a T, which is a 5.3L Vortec 5300 LM7 engine. I also know it's a Generation III 5.3 liter. No problems up to there.

But can somebody please explain where the LS designations come in? I had a look at the Wikipedia article, and it's confused me even more.

Thanks!

 

[marc1]

Are you perhaps referring to the trim level of your Avalanche? That is nothing to do with your engine RPO code or the VIN engine code etc.

 

[caravanmike]

Ls is the engine family. 4.8,5.3,6.0,6.2

 

[marc1]

Originally Posted By: caravanmike
Ls is the engine family. 4.8,5.3,6.0,6.2


Yeah or that (more likely what the OP is referring to). It is just a name to id the family like "Mark IV" family 1965 and onward (later replaced by the Mark V etc.) for BB Chevrolets as an example.

 

[Falcon_LS]

Yes, I was referring to the engine family. Sorry, should have made it clearer. Otherwise the truck is a 1500 with the Z71 package.

 

[mechanicx]

You can have 3 codes identifying a GM engine, a family or brand name like LS, vortec or ecotec etc, a single character vin code ie T, and the 3 character RPO code. LS is the engine family, T is the vin code, LM7 is the RPO code. Or at least thats the way I understand it.

 

[cchase]

The true "LS" engines are only the Corvette engines, the others use the same blocks but have different heads, pistons, intake, etc.

So the engine in your Avalanche is not an actual LSx engine just an LS-architecture engine.

That's not a great explanation technically, but it might help you head in the right direction.

mechanicx's explanation actually makes more sense, now that I think about it.

 

[OVERKILL]

Originally Posted By: cchase
The true "LS" engines are only the Corvette engines, the others use the same blocks but have different heads, pistons, intake, etc.

So the engine in your Avalanche is not an actual LSx engine just an LS-architecture engine.

That's not a great explanation technically, but it might help you head in the right direction.

mechanicx's explanation actually makes more sense, now that I think about it.


The LS3 is the engine in the Camaro right now. The LS1 was in the previous F-bodies. It is not "only" a Corvette engine. Of course the LS1 and LS2 were also used in the GTO.

And then there is the L99? LOL and the other weird variants. I'm not sure on GM's exact engine "terminology" other than it can get weird at times.

 

[moklock]

Their all just the RPO or ordering code of an engine, so the only thing real sure terminology wise is than an engine RPO is always 'Lxx'.

RPOs like LS1, LT1 became common names due to their enthusiast following. The truck engines like that LM7 just get lumped into the same family since they are based on the LS1 design.

GM has capitalized on that popularity with the LSx engines by assigning RPOs that go in a sort of sequence. More pedestrian powertrains more or less just seem to get assigned an RPO that wasn't made famous and hasn't been used for a number of years. Those RPOs may be nothing similar to a previous or related engine of the same type.

 

[Falcon_LS]

Thanks for all the input!

The terminology got pretty confusing, and now it makes more sense.

 

[addyguy]

The only LS number that matters: LS6...as in the 1970 LS6.

It didn't get much better than that......

 

[OVERKILL]

Originally Posted By: addyguy
The only LS number that matters: LS6...as in the 1970 LS6.

It didn't get much better than that......

I'd say the LS7 is better. It is a work of art, and I am FAR from a GM guy, but I have a LOT of respect for the LS7.

 

[cchase]

Originally Posted By: OVERK1LL
Originally Posted By: cchase
The true "LS" engines are only the Corvette engines, the others use the same blocks but have different heads, pistons, intake, etc.

So the engine in your Avalanche is not an actual LSx engine just an LS-architecture engine.

That's not a great explanation technically, but it might help you head in the right direction.

mechanicx's explanation actually makes more sense, now that I think about it.


The LS3 is the engine in the Camaro right now. The LS1 was in the previous F-bodies. It is not "only" a Corvette engine. Of course the LS1 and LS2 were also used in the GTO.

And then there is the L99? LOL and the other weird variants. I'm not sure on GM's exact engine "terminology" other than it can get weird at times.

I actually own a GTO, but I would still consider the true LSx engines to be "Corvette" engines applied to other vehicles

I didn't mean it to sound like it is only used in the Corvette though that's exactly how it sounds now that I look at it...

 

[OVERKILL]

Originally Posted By: cchase
Originally Posted By: OVERK1LL
Originally Posted By: cchase
The true "LS" engines are only the Corvette engines, the others use the same blocks but have different heads, pistons, intake, etc.

So the engine in your Avalanche is not an actual LSx engine just an LS-architecture engine.

That's not a great explanation technically, but it might help you head in the right direction.

mechanicx's explanation actually makes more sense, now that I think about it.


The LS3 is the engine in the Camaro right now. The LS1 was in the previous F-bodies. It is not "only" a Corvette engine. Of course the LS1 and LS2 were also used in the GTO.

And then there is the L99? LOL and the other weird variants. I'm not sure on GM's exact engine "terminology" other than it can get weird at times.

I actually own a GTO, but I would still consider the true LSx engines to be "Corvette" engines applied to other vehicles

I didn't mean it to sound like it is only used in the Corvette though that's exactly how it sounds now that I look at it...


Yeah, that was how I took it, LOL

 

[dailydriver]

Originally Posted By: OVERK1LL
Originally Posted By: addyguy
The only LS number that matters: LS6...as in the 1970 LS6.

It didn't get much better than that......

I'd say the LS7 is better. It is a work of art, and I am FAR from a GM guy, but I have a LOT of respect for the LS7.


The current, dry sumped, Z06 powerplant, or the VERY rare, old Mark 4 big block??!

 

[OVERKILL]

Originally Posted By: dailydriver
Originally Posted By: OVERK1LL
Originally Posted By: addyguy
The only LS number that matters: LS6...as in the 1970 LS6.

It didn't get much better than that......

I'd say the LS7 is better. It is a work of art, and I am FAR from a GM guy, but I have a LOT of respect for the LS7.


The current, dry sumped, Z06 powerplant, or the VERY rare, old Mark 4 big block??!


The current dry-sumped Z06 engine with all its factory titanium goodies, big bore, and toilet heads.

 

[dailydriver]

Originally Posted By: OVERK1LL
Originally Posted By: dailydriver
Originally Posted By: OVERK1LL
Originally Posted By: addyguy
The only LS number that matters: LS6...as in the 1970 LS6.

It didn't get much better than that......

I'd say the LS7 is better. It is a work of art, and I am FAR from a GM guy, but I have a LOT of respect for the LS7.


The current, dry sumped, Z06 powerplant, or the VERY rare, old Mark 4 big block??!


The current dry-sumped Z06 engine with all its factory titanium goodies, big bore, and toilet heads.


YES!

I'd love to drop one of those into my engine bay (like GM Special Vehicles/GMPP did, dry sump system and all!)!!

But instead of just leaving it pure stock (like they did), I would go with; a (slightly) bigger cam, some head porting/'clean up' work, and the humongo, 102 MM F.A.S.T. LSXR intake/throttle body setup with a full dyno tune.