Are there any signifigant differnces between in a LT1 and a LT4 engine other than cam profile and the computer? I am thinking about getting an LT from a 96 Z28 and putting it in. I was also thinking about porting and polishing the heads and maybe putting a LT4 cam in. I need to know about any other differences or computer requirments.

 

The cam, rockers, intake, heads, computer, injectors, throttlebody along with some other things that don't really effect performance.

 

Throttlebody? In what way was that different?

The biggest difference between the 2 was really the taller head ports and the different manifold needed to match up to them. The cam was actually tamer and the springs were not as strong (lighter valves).

 

So, changing the cam to LT4 and leaving everything else stock wouldn't produce any power gains?

 

Valve springs for the LT4 and the LT1 were single springs. I could be mistaken, but I believe they both used the same size springs which aren't supposed to be used with cams that lift over 0.525 in. As for the LT4 cam being tamer than the LT1, if I'm reading it correctly, I disagree. The following specs below are for each cam.

LT1
Duration at .050 - Intake - 201/Exhaust -208
Maximum Lift - Intake 0.447/Exhaust - 0.459

LT4
Duration at .050 - Intake - 203/Exhaust -210
Maximum Lift - Intake 0.476/Exhaust - 0.480 W/1.6 Rocker's

The LT1 cam was used in both Corvettes and Camaros as well. As you can see from the specs, the LT4 cam isn't much bigger in terms of Duration, but there is a sizeable difference in the lift capacity.

By changing the cam to the LT4 cam, do you mean in an LT1? If you do, yes there would be some small gains in power, but why not just get the LT4 Hotcam instead? It's a much better cam and would give a nice increase in power. Without replacing the heads and a few other things you won't get the maximum benefit, but you would get more power than with a stock LT4 or LT1 cam. Just try to avoid the "I'm buying a cam that I can grow into" crowd.

 

The major difference in the cars were the cylinder heads (raised runner heads) and the intake, which was matched w/ the heads. The raised runners allowed better flow and better power. Cams were slightly different. They had different knock sensors, the LT4 being less sensative b/c the LT1 was WAY to sensative. The programs were different in the ecm also.

 

The LT4 says "Grandsport" on it other than that its the same.

Some other things, the cranks, pistons, timing chain, balancer/damper, are different.

 

LT4 throttle body was 52mm whereas the LT1 throttle body is 48mm like stock TPI ones. The compression was a bit higher, the valves were MUCH lighter and a bit larger, the balancer was different (dual-mass), the main caps were notably stronger as was the crankshaft.

I have a really good site comparing the two if I can find it.

 

Here's a great site comparing the two.

http://www.grandsportregistry.com/lt1vslt4.htm

 

"The 48mm throttle body remained unchanged from the LT1, however all LT4 equipped Corvettes (not just Z16 Grand Sports) featured a throttle body top cover plate with the words "Grand Sport" in red letters."

 

Hmm good call on actually reading that site. Funny how many times I've read that... Guess I was wrong, thought the LT4s had a 52mm TB.

 

I thought that the LT4's had 52mm TB also, so...

 

What aftermarket heads would be good to get to make power with an LT4 cam? I want to make a good amount of power (300-350 at the wheels) but not put a fortune into it. Doesn't everyone? The motor had 285 stock, so 300 shouldn't be to unfeasable.

 

There are lots of good aftermarket heads, do you want aluminum or iron.

Don't run a LT4 cam it is not optimized for performance.

 

How much money are you looking to spend. If you're on a budget or don't care as long as it makes the power you want is a big deciding factor in what we might recommend.

 

I am on a bit of a budget, but I don't care to wait a while to save the money to get the right thing. I still woulndn't want to spend like 2000 for a set of heads, but anything reasonable I would consider. I don't really have any preferance between iron or aluminium.

 

My advice would be to order the LT4 conversion kit from summit. The kits rated at 425 H.P. and with a parasitic driveline loss figure of 20% that would leave you with about 340 R.W.H.P. to play with. The parasitic loss might not be that high mind you, but that kit does put you right in the ballpark of where you want to be. The entire kit comes with heads, cam, intake, rocker arms and timing set. You'll probably have to buy the LT4 knock module, reprogram the computer to take advantage of the mods, and maybe buy some pushrods. The pushrods might come with it. I didn't take the time to check their website. This combo will run smoothly and be completely capable of daily driving as well as knocking down some decent 1/4 mile times. Check it out.

 

Look into the ported heads/custom cam packages from Lloyd Elliot at www.eportworks.com He has a large following w/ the LT1 guys at camaroz28.com.

The LE1 package ($1100 for heads/cam) is very affordable and will out perform a stock LT4 heads/HOTcam package...

The consensus on camaroz28.com's LT1 boards seems to be the LT4 conversion package isn't really worth the coin...

 

I like the idea of either option. I'll ask around at some other boards to make sure I get the best bang for my buck. I'll more than likely get the car (wrecked Z28) for the engine/transmission and then wait and save for the intake/ head setup. Like I said, I don't mind to wait to get the power I want.

I may go ahead and switch the transmission out during spring break (funny, stay at home and spend vacation money on my car).

Either way, do you guys think it would be smarter to change the heads/ intake after I take the motor out of the donor, but before I put it in mine? Seems to me to be smarter to do the work with the motor outside of the confines of an engine bay....

 

 

I asked around at camaroz28.com. I have seen some awesome numbers over there. Ussually more hp than tq, but once it gets into the high 300s either way, I am happy.
Example:
1. 380hp/350tq (LE1 package)
2. I dynoed 417 rwhp and 381 rwtq (LE1 heads w/LE2 Cam)

That should handle most of the local **** rockets and horsemeat around here.....

 

91_5.7_TPI here is my opinion. I realize that my answer is not the question you asked. Take it for what its worth.

First off, are you getting the LT1 dirt cheap??
If not, here is what I think:
I just got done overhauling my bro's LT1 93' Z. The engine is realy not much different that an SBC with exception to reverse flow cooling, the heads and intake. It was a good improvement from SBC but it is still could use improvement, especially Opti Spark.

In my opinion, there are two choices for Small Displacement Chevy Engines. First the 350 SBC. Second LS1. If you are planing on spending $4,000.00, put into an LS1. LT1 is junk. The LT1 was the best and worst mistake GM ever made, it led us to LS1. Either Build a stout SBC or buy an LS1 don't waste money on LT1, unless its free.

Look, if anyone on these boards has wasted money hand over fist, its me. Look, I'm the morron with three Camaro's, one has been in pieces for almost a year.

Did you know, you can buy a GM New engine 6.0 LS1 345 HP for about $3,500. I know its a truck engine, but hey, think of the potential.

I am sure I will be pissing off a few people, but hey, think about it, its a true statement. LS1 is better that LT1 period. But, if its a realy good price, do it. And, I am sorry I interupted your thread.

OneBadZ4U

P.S. Its always easier to work on the engine on a stand, especially if you change the cam.

 

LT1 is the best bang for the buck. Better than TPI and LS1.

 

I am looking into the LT1 because it is what I have found that has all I need/want. It is a complete car for $2500 and it is T56. Having the complete car makes things easier when it comes to the swap.

I'm not saying that LS1 isn't better, just that the LT1 is better for what I need right now. I'm not going for the extreme, just a reliable car that I can drive from day to day and still have some extra power for fun.

If I could find a wrecked LSx with a T56, I would get it. But, buying the $3500 motor would mean having to get the wiring harness in addition to rebuilding my 700R-4 or getting a T56. That is more than I can afford at the moment. (Although, I would accept any monitary donations at this time )

 

any 700r4 wont work with the LS1, it will work the LT1

 

Oh. Well, then if I get the LS1 I will need another transmission any way. There is, however, a wrecked LS1 Z28 at the same place, but it is auto for $3500....

 

I thought the LT1 had 3 computers. One for the sensors, one for the ignition and one for the 4L60-E trans that cam with it. If that's the case then the trans will work with an LS1. Just a question worth asking. T.P.I. and the LT1 cost about the same to modify. Granted the LS1 parts are a little expspensive, but the LS1 responds a lot better to less modifications. So, I'm afraid I'm gonna have to disagree with Firebat on that one. The LS1 does cost a little more to get your hands on, but the price of the Opti-Spark units that keep going out on LT1's pushes the end cost way beyond the end cost for an LS1. I've replaced an Opti-crap ignitions on my mom's 94 Z28 a couple months ago. The dealership replaced five before that. You can use the Del-tec units to make the ignition Distributorless like the LS1, but that adds another 6-700 bucks to the total! The LT1 heads were the basis of the new Chevy Vortech heads, but the combustion chamber still isn't as efficient as the LS1 heads. The LS1 is worth 90 lbs in the weight savings department too. The LS1 also tends to sit further back in the engine bay which improves the car's center of gravity for weight transfer and handling. I'm not saying it's impossible to put an automatic in a 82-92 camaro with an LT1, but I haven't heard of any swaps regarding the LT1 using anything other than a 6 spd trans. Again, I'm not saying it can't be done, just that I haven't heard of anyone who's done it. That isn't true with the LS1. The LT1 and LS1 both require you to modify the crossmember to fit them into the car as well. Taking all this into account, I just can't agree with Firebat that the LT1 is the best bang for the buck. That's just my

 

you dont know what you're talking about.

The LT1 has one ECM. Optisparks dont go out that often. There are aftermarket products to replace the crappy optispark anyway. The LS1 is harder to mod. LT1's have been swapped with 700r4's many times. I didn't have to modify any crossmember to get my LT1 in.

 

Programming costs less for the LT1 also

 

And the chevy vortech heads were based on the LT1 heads. Not LT1 heads were based on vortech heads. Do your research otherwise, dont even bother argueing with me

 

As for the one E.C.M. part, you might be right, but the dealership claimed it had three. Yes there are aftermarket units to replace the Opti-Spark. I stated as much when I referred to the Del-tec unit. As for the LT1's working with a 700-R4 without crossmember modification, I believe I clearly stated that I'd never heard of anyone who had done one before. As to the LS1 being harder to mod, you're wrong. The LS1 responds better to modifications than any other small-block in history. Even the classic free mods work well on this engine. The LS1 also starts with better heads, cam, intake and exhaust manifolds than the LT1. Headers usually only add around 10 H.P. on an LS1. That doesn't mean the engine is hard to mod, just that it was efficient to begin with.

 

which 700R4 are you talking about? I am not talking about the one that came with the LT1 in 93. Talking about the one that is already there.

By the way, the 4L60E that came with the LT1 in 94-97 will fit without any modification. Its just an electronic version of the 700R4.

 

If you had bothered to read the post instead of whining, perhaps you would have noticed that I wrote:

The LT1 heads were the basis of the new Chevy Vortech heads, but the combustion chamber still isn't as efficient as the LS1 heads.

That means the Vortech heads only exist because of the LT1 heads.

 

Yes, the LS1 responds well to mods, but they cost more.

 

I also know the difference between the two transmissions. Like I keep trying to tell you, I NEVER said it wasn't possible. I only said I'd never heard of it being done.

 

Sorry, it was the speed reading kicking it cause you wrote a book in your first post

 

I think if you stick the same amount of money into the TPI, LT1, and LS1, the LT1 will be the fastest.

 

When you add in the cost of the distributor unit to replace the Opti-crap one, the cost of the mods isn't that much more. You have to be getting into some serious mods in order to start costing that much. The LS1 is a very efficient little motor to begin with and it responds well to mods that would cost the same no matter what motor you have. When you get into the T.B., yes, the LS1 will cost more, but it takes a lot of mods before you need to do that. I'm not trying to make the LT1 out to be a slouch. It is by no means a whimpy motor. In fact, the LS1 uses the reverse flow cooling design of the LT1 to help make it more efficient. The LS1 would not have been possible without the LT1 in some respects.

 

I do tend to write a lot don't I, lol.

 

The LS1 doesn't use reverse cooling

 

I read a book on the LS1's creation. It could be a misprint, I am open to that. But the author specifically stated that the LS1 did use reverse flow cooling. He explained that that was the reason you could bump compression on them to 11.5:1 and be safe on a stock motor.

 

Well, I can't argue with that. Hell, the trans alone with all the pedals and crap is amost worth that. You are pretty much getting it dirt cheap, so forget about my rambling.

 

Its not Vortech, its Vortec, do your research!

 

Yeah, ok. Now I think I am afraid to lift my hood.

Let's try this. Which one is easier to install? The LS1 auto or the LT1 manual. Discounting the pedals. And are there any aftermarket head/cam combos like the ones available @ www.eportworks.com ?

Not to argue, but I thought LS types were reverse flow as well...

Either way, there all

 

No, LSX is not reverse flow. The LS1 was a completely new design, All-aluminum, with 6 bolt mains, etc.

All i've heard is that the LS1 is harder to install. I dont know how much harder.

The LT1 with the 6 speed manual. You have to cut a hole underneath for it to fit and some other work. Again, dont know all the details, I've never done it.

so, either install wont be easy from your choices. They shouldn't be too hard either. Most engine swap stuff for these engines is covered in the engine swap forum here.

 

Just build a 70s 350 4-bolt block and put LT1 heads and intake on it and slap a nice cam in. I like mine

I'm also pretty sure the LSx series are reverse-cooled because as stated, that helps with being able to run higher compression. Keeps the heads cooler.

Don't know if I'd rather have an LS1 or LT1. If I had enough money to get one and tune one, I'd take an LS1. However, I'd almost take an LT1 instead and run a distributor ignition on it. Then again, that'd be just like running a Gen 1 SBC with LT1 heads and intake (oh wait...), cept with the true LT1 you'd get reverse flow cooling, which is a plus.

Can't argue with the 90lbs weight savings. Wtih some LS1 cars touching 12.99 stock, that's almost 11s in a thirdgen with good suspension it seems. Throw long tubes and a mild cam in an LS1, and you're putting out 350-360rwhp.

Then again, LT1s with LE2 ported heads have 410rwhp+, so choose your poison.

 

LT1 vs LS1 threads
https://www.thirdgen.org/techbb2/sho...ght=lt1+vs+LS1

and read post #3 on this thread.
https://www.thirdgen.org/techbb2/sho...ght=lt1+vs+LS1

oh, did it say LS1's are not reverse-cooled?

also read here:
http://www.idavette.net/hib/ls1c.html
http://www.racersden.net/forum/archi...p/t-13306.html

Or how about you just ask any of the LS1 guys on this board.

 

Either way its unimportant. The LS1s can run high compression, just like LT1 cars, reverse-cooled or not.

This thread is about LT1 vs. LT4 not LT1 vs. LS1.

I'd skip the LT4 conversion kit and pick up an LE2 head/cam kit. Cheaper and more power. 425hp at the flywheel or 425hp at the wheels while saving $1000? Good question..

I plan on going LE2 this winter if I can save up enough cash. Depends if I plan on going somewhere for spring break or not. This spring break will probably be spent on/with car though.

 

.

 

Maybe we should change the topic name to "LT1 vs LT4 vs LS1". For what I need and want right now, I think that the LT1 will be better, especially when you throw in the that fact that I can save the 1000 on the LT1 and add a 100 or so dollars and get the LE1 head and cam from Lloyd.

I am pretty sure that the LS motors are better than LTs, mainly because things get better each time around.... ussually. If I had the exra cash and wasn't trying to go to college at the same time, I would get two or three (maybe four) jobs, and get a new 6-speed and an LS7 and be done with it.

I think that the LT4 is not as good of an idea as the even the LE1 heads and cam.

OK, now, what about the AC compresser and knotching the k-member? I thought you had to buy a new AC relocator braket for that?

BTW, to get the advertised HP, Lloyd recomends long tube headers, so are there any serious issues with them (clearance, fit, etc.) verses the shorties from Hooker Super Comp?