Question: What is the Difference Between a "LT" verses "LS" Corvette Engine?

[tim414]

I was wondering what the major differences are between a (Vette) 'LS' verses 'LT' engine?? As far as technology which engine is most efficient on fuel but still posess high degree of performance? Which is most durable? I have been wondering if one of these engines would be suitable for a older Pontiac ('69) which weighs close to 4k lbs.....I am also wondering which engine is most adaptable to older (GM) muscle car applications? Which engine gives a budget minded guy the most bang for his buck??....anyone (GM) tech or have experience building/restoreing (GM) muscle out there with this insight??? Thanks...Tim

 

[c4c5specialist]

HI there,

LT1 or LT4 is a generation 2 small block and is engineered for higher rpm power.

LS1 is a generation 3 small block and more engineered for all around power and performance. I prefer these from a reliability standpoint ONLY from the ignition system.

Allthebest, c4c5

 

[1963SS]

LT1 and LT4 engines are made from good old American iron and the LS engines are made from recycled Old Milwaukee beer cans. The LT engines have a sleek plenum and twin intakes on the aerodynamic throttle body. The LS engines have these ugly looking curly things on top that resemble a Jamaican drug dealer's dreadlocks and the single opening throttle body that looks like some streetwalker about to get it in the kazoo going "OOOO"! Other than that......not much difference.

 

[Hib Halverson]

I was curious about the statement that GM's Gen 3 and Gen 4 V8s are made from recycled "Old Milwaukee beer cans". What's the source for that information?

 

[WillC4]

I was wondering what the major differences are between a (Vette) 'LS' verses 'LT' engine?? As far as technology which engine is most efficient on fuel but still posess high degree of performance? Which is most durable? I have been wondering if one of these engines would be suitable for a older Pontiac ('69) which weighs close to 4k lbs.....I am also wondering which engine is most adaptable to older (GM) muscle car applications? Which engine gives a budget minded guy the most bang for his buck??....anyone (GM) tech or have experience building/restoreing (GM) muscle out there with this insight??? Thanks...Tim

Well there are quite a few differences between the Generation II LT engines and the Generation III LS engines.

The LT1 was a Cast Iron 350 (5.7L) SBC engine produced from 1992-1997 used on the F, B and Y bodies. The F body LT1 had 275-285 HP and 315-325 ft-lbs of torque. The Y-Body LT1 had 300 HP and around 340 ft-lbs of torque.Not sure what the B-body numbers were. On both F and Y Bodies it had aluminum heads while b-bodies had cast iron heads. There was a special performance version of the LT1 called the LT4 that was featured in 1996 corvettes with 6 speed manual transmission, that produced 330HP and i belive 340 ft-lbs of torque, but it is believe that gm underated these values. The LT also had a aluminum intake, twin butterfly throttle body, timing chain driven water pump, reverse cooling, and a front mounted distributor called the optispark (probably the only flaw in this engine in my opinion). The LT1 is a unique engine from gen I SBC, but some parts can be swapped between the two. They also share sametransmission bolt pattern, displacement, engine mounts and overall block shape as Gen I SBCs. For performance, the LT1 responds very well to bolts ons, forced induction, nitrous, stroker displacements, you name it. The price of LT1s out there is pretty cheap and can be built up on a budget.

I dont know too much about the LS1, im sure someone can elaborate on it with you. What i do know is that it was Gen 3 SBC 346 (5.7L) all aluminum block that produced 345-350 HP on Y-Bodies and 305-325 HP on the F-Bodies. I have looked at pricing on them, and they are still more expensive to build up then a LT1 from what ive researched.

Now, performance between the two. There is a HP gap in the Y-body numbers, however with a same budget spent on upgrades for both, they are pretty much equal. So its a matter of preference now, i say go with the LT1 if you want to put it in a older muscle car because it pretty much can mount directly into the points were Gen I SBCs can be mounted and it a little less expensive as well then a LS1. Of course i prefer the LT1 is because its the motor i have personally been working on for years, i have had a Lt1 camaro, and now on my LT1 corvette.

So, theres my opinion on what you should go with, both are good engines, but i think the LT1 is more to your tastes for an old muscle car.

 

[warren s]

I had 2 cars with LT1s and 2 with LS1s

The LS1s have more power stock across a wider rev range. 50hp is nothing to sneeze at.

I also found the LS1 to be more receptive to simple power adders. LT4s for project cars are few and far between. Either engine requires some associated electronics to reach its full potential. The LT1s you see at cars shows with the tiny air filters clamped onto the end of the plenum running in open loop dont perform all the great. (Blanket statement - only drove a handfull)

Either mill will move an old Poncho (I had my share of those!) and given the choice I would go with an LS1. There seems to be more aftermarket support for the LS engine series now than the LT1s. Being produced up to 2004, you have a very good chance of getting a good deal on a “seasoned” LS1 or a 405 hp LS6.

The old 455s and 400s of Pontiac fame with gross torque figures in the 400 to 500 foot pound range would be hard pressed to out perform an LS1. (Stock)

 

[1963SS]

I was curious about the statement that GM's Gen 3 and Gen 4 V8s are made from recycled "Old Milwaukee beer cans". What's the source for that information?

Uh-oh, I've been caught by the HIBmeister. I don't really have a source and all I really have is circumcisional evidence. They're both aluminum and since some people recycle maybe the LS engines are made from beer cans.

Seriously though, I don't have any experience with muscle cars other then a 95 Impala but here's a little project that went really well. I do like the aesthetics of the LT1/LT4 over the aluminum generation.

Recipe for a lot of laughs. Take an old Datsun, put on sidepipes, and enjoy the stares.

Stuff a LT1 in there instead of the inline 6, dress it up a fuzz, and enjoy the ride. Datsun's aren't supposed to sound like that. This is what I like about the LT engines. A harness, an ECM and an engine....you're done.

Of course, the 4L60E needs a driver interface or a human control module. Sounds kind of sci-fi, huh??

 

[warren s]

Thats really cool !!! How did it run??

 

[tim414]

Well there are quite a few differences between the Generation II LT engines and the Generation III LS engines.

The LT1 was a Cast Iron 350 (5.7L) SBC engine produced from 1992-1997 used on the F, B and Y bodies. The F body LT1 had 275-285 HP and 315-325 ft-lbs of torque. The Y-Body LT1 had 300 HP and around 340 ft-lbs of torque.Not sure what the B-body numbers were. On both F and Y Bodies it had aluminum heads while b-bodies had cast iron heads. There was a special performance version of the LT1 called the LT4 that was featured in 1996 corvettes with 6 speed manual transmission, that produced 330HP and i belive 340 ft-lbs of torque, but it is believe that gm underated these values. The LT also had a aluminum intake, twin butterfly throttle body, timing chain driven water pump, reverse cooling, and a front mounted distributor called the optispark (probably the only flaw in this engine in my opinion). The LT1 is a unique engine from gen I SBC, but some parts can be swapped between the two. They also share sametransmission bolt pattern, displacement, engine mounts and overall block shape as Gen I SBCs. For performance, the LT1 responds very well to bolts ons, forced induction, nitrous, stroker displacements, you name it. The price of LT1s out there is pretty cheap and can be built up on a budget.

I dont know too much about the LS1, im sure someone can elaborate on it with you. What i do know is that it was Gen 3 SBC 346 (5.7L) all aluminum block that produced 345-350 HP on Y-Bodies and 305-325 HP on the F-Bodies. I have looked at pricing on them, and they are still more expensive to build up then a LT1 from what ive researched.

Now, performance between the two. There is a HP gap in the Y-body numbers, however with a same budget spent on upgrades for both, they are pretty much equal. So its a matter of preference now, i say go with the LT1 if you want to put it in a older muscle car because it pretty much can mount directly into the points were Gen I SBCs can be mounted and it a little less expensive as well then a LS1. Of course i prefer the LT1 is because its the motor i have personally been working on for years, i have had a Lt1 camaro, and now on my LT1 corvette.

So, theres my opinion on what you should go with, both are good engines, but i think the LT1 is more to your tastes for an old muscle car.

It almost sounds like LT is the way to go....although (besides having LT in SUV) never had much exp w/LT....LS is what I am familiar with. They are high reving...lots of power...torque value does not seem to add up to LT though...and pushing a heavy car one would need plenty of torque...would'nt I? I also wonder if LS would fit into the bay of my old Pontiac I bought (w/out a motor)...still has it's old auto 3 speed tranny in it though. I'm thinking it will need to go as well. Is this going to be doable??? Without haveing to change up the engine bay???

 

[warren s]

Either engine will fit and do the job. It will be a decent amout of work and expense.

I would check to see what retrofit kits or systems are available. It may cost much more than just getting a rebuilt 400 Poncho motor

What Pontiac did you buy?

 

[c4c5specialist]

Just remember, accurate replacement parts for LT1/LT4 are more scarce than LS1/LS6.

You cant even get a crate motor anymore from GM.

Allthebest, c4c5

 

[tim414]

Either engine will fit and do the job. It will be a decent amout of work and expense.

I would check to see what retrofit kits or systems are available. It may cost much more than just getting a rebuilt 400 Poncho motor

What Pontiac did you buy?

I need to find a engine code book. There are so many people out there that will tell you they have "old muscle" car engine for sale. The one the guy had to put into this Pontiac I bought (luckily checked engine stamp code before I bought it) told me it was a old Pontiac engine (400) but after checking (my friend knows somebody that has the codes) we found that this was a engine that GM put into regular cars (like chevy Impala). It's definitely a 'mine-field' out there these people claiming that they have 'rareity' engines......I went ahead and bought the old car but left him w/engine. It has it's old tranny in it (3-speed auto). The car is a 1969 Grand Prix model 'J', which would have had the 400 in it. Grand Prix was Pontiac's flag ship car....combined performance and luxury. Had a 'model SJ' (1969) as my first car. That's why I'm so hell bent on having another one....sure are hard to find. I did not know that these cars were sorta special at the time or I would have put it in the barn out of the way for the past 30 years!!! If I cannot locate a Pontiac 428 (67-69 or maybe even 1970-1971 went to 455 I think) then I'm staying with the LS. I know that C4C5specialist knows his stuff. He said in earlier thread that the LT is hard to find parts for. Don't want that.

 

[tim414]

Just remember, accurate replacement parts for LT1/LT4 are more scarce than LS1/LS6.

Thank you sir. I am going to stick with LS if I cannot locate a 428 or maybe will settle for 400. I want a 428 but I have not come close to finding one. I do not have a code book that details info how to determine the engine stamp codes. Have a friend who knows someone with one and come to find out I almost bought a 400 that this guy claimed was a period correct Pontiac engine....come to find out it was a early 70's chevy 400 that would've been in a regular car (like Impala). Infuriates me that people will tell ya anything to make a quick buck. Needless to say I let him keep that engine. The old car I bought is a 1969 Grand Prix model 'J'. My first car was a '69 GP model 'SJ' with a 428-fully loaded. The ones I have came accross are not for sale. You just don't come accross those anymore (model SJ with 428). Know how I can get my hands on a code book to decipher the engine stamp codes? Thanks man.

 

[tim414]

Well there are quite a few differences between the Generation II LT engines and the Generation III LS engines.

The LT1 was a Cast Iron 350 (5.7L) SBC engine produced from 1992-1997 used on the F, B and Y bodies. The F body LT1 had 275-285 HP and 315-325 ft-lbs of torque. The Y-Body LT1 had 300 HP and around 340 ft-lbs of torque.Not sure what the B-body numbers were. On both F and Y Bodies it had aluminum heads while b-bodies had cast iron heads. There was a special performance version of the LT1 called the LT4 that was featured in 1996 corvettes with 6 speed manual transmission, that produced 330HP and i belive 340 ft-lbs of torque, but it is believe that gm underated these values. The LT also had a aluminum intake, twin butterfly throttle body, timing chain driven water pump, reverse cooling, and a front mounted distributor called the optispark (probably the only flaw in this engine in my opinion). The LT1 is a unique engine from gen I SBC, but some parts can be swapped between the two. They also share sametransmission bolt pattern, displacement, engine mounts and overall block shape as Gen I SBCs. For performance, the LT1 responds very well to bolts ons, forced induction, nitrous, stroker displacements, you name it. The price of LT1s out there is pretty cheap and can be built up on a budget.

I dont know too much about the LS1, im sure someone can elaborate on it with you. What i do know is that it was Gen 3 SBC 346 (5.7L) all aluminum block that produced 345-350 HP on Y-Bodies and 305-325 HP on the F-Bodies. I have looked at pricing on them, and they are still more expensive to build up then a LT1 from what ive researched.

Now, performance between the two. There is a HP gap in the Y-body numbers, however with a same budget spent on upgrades for both, they are pretty much equal. So its a matter of preference now, i say go with the LT1 if you want to put it in a older muscle car because it pretty much can mount directly into the points were Gen I SBCs can be mounted and it a little less expensive as well then a LS1. Of course i prefer the LT1 is because its the motor i have personally been working on for years, i have had a Lt1 camaro, and now on my LT1 corvette.

So, theres my opinion on what you should go with, both are good engines, but i think the LT1 is more to your tastes for an old muscle car.

Thank you sir for sharing your knowledge. i found it very helpful.

 

[warren s]

Sorry to go off on a tangent....

A 69 GP SJ ! Real nice car.
I can relate to old Pontiacs. I had 3 GTOs, 2 Grand Prix’s, 2 1974 Grand AMs and a Firebird Formula.

You have a lot of options with that car as far power plants. Anything from a 389 to a 455 will fit with a minimum of effort and use off the shelf stock Pontiac parts. The performance difference between any of the available Pontiac motors is negligible for a street car of the size and weight. A very wide variety of blocks both 2 bolt and 4 bolt mains are still out there.

Going with an LT1 or LS1 will require much more custom work.

The 428 came in a bunch of Pontiacs from GTOs to Station Wagons from 67 to 69. The lower performance blocks from 69 had 2 bolt mains. (Pontiac motors with 4 bolt mains on have 4 bolts in the center caps)

The LS1 by comparison has 6 bolt cross bolted mains

1969 (350 c.i.d.) #9790079
1969 (400 c.i.d.) #9790071
1969(400 RA IV) #9792506
1969 (428 c.i.d.) #9792968

 

[tim414]

A 69 GP SJ ! Real nice car.
I can relate to old Pontiacs. I had 3 GTOs, 2 Grand Prix’s, 2 1974 Grand AMs and a Firebird Formula.

You have a lot of options with that car as far power plants. Anything from a 389 to a 455 will fit with a minimum of effort and use off the shelf stock Pontiac parts. The performance difference between any of the available Pontiac motors is negligible for a street car of the size and weight. A very wide variety of blocks both 2 bolt and 4 bolt mains are still out there.

Going with an LT1 or LS1 will require much more custom work.

The 428 came in a bunch of Pontiacs from GTOs to Station Wagons from 67 to 69. The lower performance blocks from 69 had 2 bolt mains. (Pontiac motors with 4 bolt mains on have 4 bolts in the center caps)

The LS1 by comparison has 6 bolt cross bolted mains

1969 (350 c.i.d.) #9790079
1969 (400 c.i.d.) #9790071
1969(400 RA IV) #9792506
1969 (428 c.i.d.) #9792968

Thanks (is it Warren?) man....are these the actual numbers stamped on block? My original SJ had the 428....I soooo wish I could find one 'intact' that the owner was interested in selling. I found several but the owners would not part with either of the.....one was almost identical to the one I had....almost brought tears to my eyes. Never thought I would see one again. These guys that have them know their special....and will not let go of them. My family had a 1973 Grand Am, had the slanted front fascia....I liked that car....there was also this guy who had contacted me, told me he had a GP SJ w/428 and very straight body....asked him to email pics....cause I've been on a wild chase before....and thats exactly what it was...wild....I have not heard from him since....begin to wonder if he was b.s.'ing me....would'nt be the first time.

 

[warren s]

Yes, thats engine code for the 428 block. (I should say casting as Pontiac used the same blocks for 350s to 455s - yes a Pontiac 455 is a small block).

I dont remember if the casting numbers were any differnt on the blocks for the GTOS, GPs or wagons. The heads and other components sure were.

There are 100s of Pontiac websites out there, I would try searching for a 428 on the internet.