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difference between LT1 and LS1?

693 Views 16 Replies 11 Participants Last post by  hwk60
does anyone know what makes them different? I have a chance to get an LT1 for under 500 bucks complete long block, fuel injector system and aluminium heads included.
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Big difference. The LS1 is all aluminum for one.
I think the LS-1 has individual coil packs on the top of the valve covers while the LT-1 has the standard distributor and wires.
LS-1 is a completely different engine. Heads, block and all internals are different from the old small block Chevy's. LT-1 is a great engine also, but not really comparable to an LS-1. If you can get an LT-1 for less than $500 and it's in good shape ie low miles and complete, then that's a good deal. I am thinking of finding an LS-1 for my 240 at some point down the road. I've also thought of the 4.2L I-6 from the Trailblazer/Envoy. That would be a cool engine, but might be too tall.
an LT1 is good, but with the aluminium cylinder heads its better, and with a mild cam and better flat top notched pistons with a double shot of 200 hp NOS, its better than any LS1 ever thought about being.
An LT 1 for $500 is a good buy. The LS 1 as mentioned is all aluminum with separate coils and has about 335 RWHP compared to LT1's ~300 RWHP.

The LT 1 is much cheaper to build compared to LS1, but expensive compared to regular 350. Also remember you will need the complete wiring harness MAF and PCM. Complete LT1's are usually close to $1000 so definitely a good deal. Harness and PCM are ~200 and then you need to reprogram it to be a 94/95 Camaro.

The LT 1 will bolt into your existing engine mounts but you will need to buy an AC delete and fabricate a power steering delete. Not hard to do, the power steering on an LT1 connects where the passenger engine mount is on your 350 in your Z.

The LS 1 requires different engine mounts entirely from what I understand. Another difference is LS1 is strictly OBD11, LT1's were OBD1 94/95 Camaro and OBD11 in 96, but can be converted to OBD1 with a few resistors on PCM.

OBD1 is far cheaper to program and modify, OBD11 tools cost roughly twice as much. Porting the MAF, putting good exhaust, reflash the PCM, and you will have close to what a stock LS1 gives.
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You watch too much fast and furious!

A motor is limited, putting 400 HP NOS on an LT1 will NOT produce an additional 400 HP!

An LT 1 will take 150HP maybe 175 above that and all you will do is decrease HP!

On your statement about aluminum heads.

Actually if your goal is to produce more HP the iron heads flow better. Stock about 20% and with porting they have a much higher flow than the aluminum (easier to put large valves instead of 1.94/1.5).

Then with a Cam ~220 duration at 50 and NOS could get you 500RWHP. And Lt 1's come stock with small chambers and high compression (~10.2 LT4 10.4)

Post Edited (Oct 15, 10:31pm)
I believe I heard somewhere that the LS1 weighs about the same as an L28, making it the preferable engine of the two, cost of course neglected.

but yes they are totally different - the LS1 isn't even a 350 - its a 346. I'm fairly certain that NONE of the internal engine parts are interchangeable.

LT1s had something called opti-spark, which is a big PITA. My roommate has a 95 Z28 and he's had to replace it twice, first time 'cause it wore out, the second time because when the water pump wore out, it leaked antifreeze onto the opti and destroyed it. Its basically a distributor mounted under the water pump.

hey Him - haven't seen you in awhile!

I have a question - about the aluminum/vs iron heads...and I'm talking from a purely stock perspective. The Al head Camaro LT1 makes 15 more hp than the Impala SS iron headed LT1. If the iron head flows more, then why does the Impala have less hp? I'm not being a smart ass or anything, I really want to know. I always assumed it was the heads but it could be cam or ECU programming.
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The Impala's computer is programmed differently. You can reprogram it but this will change shift ponts, fuel economy, etc.
LT1's have big ignition/water pump problems.

LS1 is a much better engine. Plus you can find LS1's in good shape.

FYI, the truck versions of LS1's have cast iron blocks and come in various sizes. The 6.0 liter being the most desirable. The LS1 5.4 truck engines complete with trans are cheap. However, the computer mods and wiring to needed to control the LS1 adds a bunch of money.

Edelbrock makes a new intake to put a holley on an LS1 but not sure how they handle the ignition control.
Hey Him, I was just joking about a double shot of 200hp NOS. All i really want to do is get rid of my crate 350 for a newer flashier engine that will be lighter and more hp. I plan on driving the car daily. I really hope that this LT1 is lighter than my carbed 350. I also hope to put a race ready rebuilt 700r4 with overdrive on it. A nice guy from Florida has been giving me some good tips. He is Maddog Transmissions, owners name is Lou, he said if i drive there he will fix up my car with a rebuild and buy me lunch, all for the low low price of $1350
An aluminum LT1 is roughly 50 lbs lighter than a ‘standard’ 350. An LS1 is all aluminum so yes it is even lighter than an LT1, and as stated totally different than LT1 or early 350's. I know a V8 is supposed to be ~200 pounds heavier than L2X’s so LT 1 ~150lbs different, therefore an LS1 MIGHT be the same weight as an L2X.

LS 1's could be same weight I don't know, I have never weighed an iron versus aluminum block, bit I feel they are at LEAST 50lbs lighter so no more than 100 lbs heavier than an L2X. Also, remember a V8 is shorter so the center of gravity tends to be more rearward and moving the weight rearward is ‘better’.

Optispark has many that love them, and many that hate them. They are DEFINITELY sensitive to moisture. If antifreeze gets inside they usually are trashed (antifreeze does not evaporate). Depending on use they can be extremely useful since they produce high resolution pulses enabling exact timing for systems external to GM's PCM.

The Impala have iron heads, 3" vs 3.5" MAF, and have a much smaller Cam. The differences can be seen at


I helped a friend put an iron headed Impala in a truck he changed the cam, MAF and exhaust manifolds and it is a totally different engine. Also remember in Impala the air box and exhaust are different (manifolds are tiny on an Impala relative to a Camaro). It amazes me with a Cam difference of ~.418 vs .45 lift and 191 vs 202 duration, MAF differences they only lose ~25 RWHP (Most irons rated 260 many Camaro's 285). The 300 RWHP models are supposed to be due mainly to improved exhaust and air intake.

But since the Impala is a heavier vehicle GM wanted it to have better bottom end which an Impala definitely does relative to a Camaro

$1300 for a rebuilt 700 I would say he owes you more than lunch! IF you use an LT1 I would get the electronic transmission, it is an ‘upgraded’ 700 and provides superior control since you can program all shift points and they are repeatable! To make sure you know what I meant $1300 for a 700 is NOT a deal IMO!

Where have I been? I usually visit once a week. Seems most my posts were arguments so I decided the easiest way was to simply not visit. From what I have seen here the arguments are still common but since I’m not part of them I feel better. Also I’m <50% done on my supercharged LT 1 280 still hoping for early Jan. Building a roll cage now all it takes is time, and more money than expected.

PS Also don't worry about buying a Camaro harness. You can get one from an Impala cheaper and only difference is the MAF and code in PCM. Get a Camaro MAF and I or many other people can reflash the PCM to a 94/95 Camaro. That model is chosen because it is OBD1 and provides easy mod's to get additional performance. Custom tuning is not expensive, do NOT use a hypertech (hyper trash is what most call them).

Email me if you really get motor I have all the tools and can steer you to what is effective and what is a waste.

Post Edited (Oct 16, 8:40am)
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The LS1 weighs about the same as an L28 but it really needs to be compared to the L28ET since an N/A is no comparision HP-wise. The LT1, especially with alum heads, is a little heavier but a nit when considering a V-8 swap. With the use the JTR kit or a full setback, either of the V-8 engines will sit behind the axis of the front wheels and have better F-R weight distribution than with the stock L28, busting the myth about V-8 swaps making a Z front heavy.

.......I'm an Optispark lover / hater.

The system is (almost) foolproof, and will simply spin generating the pulse for as long as the bearings hold out.

On the hate side, the biggest downfall is the inability to access it because it's mounted down low on the timing cover, (correct - below the water pump) but, it's sealed, and you generally have no reason to visit with it, and there are no internal parts you need to mess with.

The later models are plumbed with a vent system to further avoid any water infiltration.

Additionally, the water pump system has two advantages.........it's set up
so that it - reverse flows - cooling water through the heads first, then down through the block. A BIG advantage to keeping the head temperature within livable limits. Second, it's direct shaft driven through the timing cover also, so it has no side loads on the shaft bearings from belts, etc. Again, it also will run as long as the bearings hold out.

230,000 on the latest one, one water pump change, and overall, it runs like a top.
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6.0 Liter

....from the truck application is called an "LQ-4". It is in the LS-1 family, but does not share the same intake manifold. Not sure about other differences between LQ-4 and LS-1 but I think the heads and cam are also different.

The latest version is in the new 'Vette and is called an LS-2. Impressive specs on the new 'Vette motor.
Thanks for your input Jack(him) and your offer to help a guy out with his LT1 swap. I have every intention of getting that motor into my 280z. I'm going to ask maddog Lou if he has the elec version of the 700r4. I understand his $1300 price is mainly due to the fact that the tranny he rebuilds to race specs, uses 9 pads instead of 5, corvette servo, and other stuff. But if the L460E or what ever it is.....if its an upgrade, i'll look for one. Mainly want a reliable overdrive for highway cruises.

PS Lou said his 700r4 can handle 700hp
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