Well, the title says it all.

There are plenty of fast cars on this site. Everything from carburetors to twin turbos. Every kind of engine known to man (or at least GM) has been put in one of these cars. I especially like the 11 second 87 Trans Am with the mostly stock 455 Buick in it. It has working A/C and cruise as well. I also am very fond of the Turbo V6 Buick cars here as well.

So, here it is. What is so special about the LTx or LSx engines? Are they not all pushrod V8s? Do they not all run intake on the top and exhaust out the sides? Don't they all run a cam in the block? I know that most of them run an updated engine management system, but that can be retrofitted to any older platform with a little ingenuity and some hard work. I am asking about the basics of the engine, what's the magic?

I am honestly asking so as to influence my selection of upcoming project pieces. I am not bashing or trashing - I want to know what is so good about them that I should not look at the old stuff anymore.

LT1 seems like a 350 Chevy with a wacky Smokey Yunick cooling system. Other than that, what's better? Is reverse cooling somehow proved to be better in the 1/4 mile or at the gas pump? The rest of the parts can be made to fit the older small blocks...

LSx is a new design sharing nothing with the old chevy engines. It uses some common parts with the 3800 V6 engines along with some valve train geometry. It has big rectangular ports like my old Buick and Olds engines, nothing special there. Two valves per cylinder, right?

Where's the magic??

 

heads! bassically that's what it really comes down to. then the factory improved intakes.

this is why don't care for the lt1 my self. it shares alot of very basics as the old 350 blocks with the updates?? (yes better rods, lighter pistions, better intake vs the tpi) and rev. cooling. optispark had issues in the first years and the water pumps did leak now and then which all engs (l98,lt1,ls1 ect)will do but since the opti spark was right under it It would/could get a bath.

LS1 just plain out has better heads and intake setup.


as a result each year the factory bassically improved and tweeked HP and drivability so the newest is usuallly better most want it.

now since it's on the roads in in the thousands we can get our hands on these power plants cheaper than the aftermarket upgrades usually will cost for the older eng.

 

Pretty much what 88 350 said. The blocks are actually different than the older 350's (thus the reason they're called GenII but the vortecs are still GenI) and really only share the same bearings and oil pump, pretty much everything else in the engine is different. Powder metal rods (stronger than the pink rods) hyperutetic pistons (over cast aluminum) and a completely different crank. Reverse flow cooling allows the compression to be bumped to 10.5:1 in the LT1s and the intake is far superior than any tpi setup out there. The engine management in the '94 and '95 are OBDI with flash capability instead of burning proms, '96-97 went to OBDII with the addition of the crank sensor and two more O2 sensors. This motor is far superior than the TPI L98 motors and can take the revs more (seen some personally turn 7300 on the stock bottom end, stock ported intake with a set of MTI ported heads with a CC306 cam)

LSx series is pretty much the beast of the current small blocks, they can take .650 lift cams with ease (with a spring swap) respond to mods better than any others out there, the heads are made more like a big block instead of the small block with valves being staggard intake exhaust, intake exhaust, intake exhaust, intake exhaust instead of exhaust intake, intake exhaust, exhaust intake, intake exhaust. Almost 11:1 compression, likes the bottle and/or force induction without having to change anything, coil packs instead of distributor.

I've rode in a TPI car, not bad but my LT1 would smoke it, and my LS1 4th gen would eat my LT1 for lunch, I'm sticking with the Gen 2 and Gen 3+ motors.

 

Everything above is making my point.

The LT1 intake can be had on this site with all parts attached for less than 200 bucks. The PM rods can be had on a budget as well. The reverse cooling does what exactly to allow 10.5 to 1? I run that on normally cooled engines... Is there something about the LT1 crank that makes it better? What? Hypereutectic pistons are not expensive if you're gonna rebuild your engine anyway.

All of the sensors and engine management can be swapped from either engine to something older.

As for LSx engines, what makes them take .650 lift with ease? Why do they respond to mods better than any others? I understand the mega heads; they can also be had for older engines.. I also like 11 to 1 compression on older stuff. I don't like fractured cap technology for the newer modular series. I don't like the thin block castings although it's not a big deal to sleeve cylinders back to standard. The stock pistons are not choice, in our work trucks and vans with these engines it takes only one overheat to do something funny and then there is a piston knock. I hear about it over and over with these engines, whether in 4th gens or trucks, so I guess aluminum or cast iron block doesn't matter.

I think an older 350 or 400 can be brought to LT1 type power simply by using LT1 parts from either the wrecking yard or a classifieds site like this one. Ditto the engine management. The LSx series is a whole new thing, so I'm still looking at it...

 

All of the following info comes from a guide that Doug Anderson put up here http://www.automotiverebuilder.com/ar/ar99928.htm

Compared to the 1991 Chevy 350 L98 with TPI, the LT1 made 20% more horsepower, got better fuel mileage, and had a much broader torque band with 90% of it’s peak torque available from just over 1,000 rpm all the way up to nearly 6,000 rpm.



BLOCKS
350 - There are two blocks, one with two-bolt mains and one with four-bolt mains. They both have the same 10125327 casting number, so there’s no sure way to know which one you have until you get the pan off. However, if it came out of a Corvette, it should be a four-bolt block, and if it came out of anything else, it was supposed to be a two-bolt. GM used the two-bolt block for everything but the Corvette because it had plenty of strength and it weighed a little bit less.

CRANKS
350 - The crank for the LT1 looks just like the one in the late 350 and has the same casting number 14088526, but it’s balanced for the lightweight pistons that were installed in the LT1. Be sure to keep these cranks separate so they don’t end up in a regular 350, and don’t ever use a regular 350 crank in a LT1. In fact, if you are short of LT1 cranks and don’t have a balancing machine in your shop, you would be better off using a crank from a 305 instead of a 350 because it’s actually closer to the balance specs for the LT1 crank.


Rods
350 - The original LT1 came with regular forged 350 rods, that were shot peened for localized hardness under the head of the bolt and nut. Powdered metal rods were phased in for the Corvette around 1994 and used in all of the LT1 engines by 1995. GM made the change because the powdered metal rods were cheaper to make and were much stronger than the GM high performance "pink" rods. In fact, they are supposed to be good for up to 450 hp. They are machined at the parting line so they can be reconditioned.

HEADS
There were two heads used on the 350, one aluminum and one cast iron, along with one cast iron head for the 265. GM claimed that the original LT1 aluminum head had a 15% increase in airflow as a result of revised port angles and higher port ceilings when compared to the 1991 L98 head. That was impressive in 1992, but the iron LT1 head that came out in 1994 was even better. It flowed 20% more on the intake side and made more horsepower on the dyno.

As for the reverse flow cooling, it cools from the heads down, not from the bottom of the engine up, thus allowing the 10.5:1 compression and 44* timing advanced to be able to run, producing more power. At an idle, my LT1 is running 25* of timing non-advanced.


The whole point is, yes you can go out and buy these parts for a normal L98, but when you put it all together with a good intake (last time I looked, LT1 intake was selling the modified intakes for around $500) you would have just as much in it if you had bought a stock LT1.

 

Thanks for the info. It does help quite a bit.

I think after you spend all that money you'd have a fresh older engine versus a used LT1. Not that that's bad, I love used stuff.

After seeing that, I would say that if I ever get a "smokin' deal" on an LTx, I'll get it and fit it in something. As an sbc, it looks to be a desirable piece.

 

The main reason that the LSx can run wilder cams without any modification is the 15* head angle compared to the 23* of the Gen1 SBC.

 

my question is this...how come LT1's seem SOO strong compared to any other GEN I small block?

Guy on ls1tech just dynoed 429whp thru a T56 with a heads/cam package from Advanced Induction. cam specs are less than 230 degrees at .050". heads are 200cc heads which probly flow upwards of 280cfm at .600", if not more!

In theory, if you put those heads/cam on a small block chevy 350 with same compression, it should make identical power... but often i never see any streetable small block 350's making anywhere NEAR 400whp on the street. if you had aluminum heads that flowed as good as the AI 200cc heads and that exact same AI custom cam, and a comparable intake like HSR or miniram, that 350 should RUN HARD!

Like i say tho, most combos on this board i'm not very impressed...compared to what LT1 guys are doing. they make 350whp with just a cam swap on stock heads!!!

Is it the ECM control? Sequential injection over other batch fire units like our TPI computer systems?

 

Sequential only helps with idle quality and emissions, when spinning higher rpm and under load the injectors arent going to spray any more accurately since you pretty much have to be spraying at the valve with it closed to get enough fuel in for the power.

Some of it may be the reverse flow cooling, allowing increased compression and more aggressive ignition curve, add to that the optispark is highly accurate which may help some with fine tuning the ignition map also.

 

The more of this that I read, the more I am convinced that is the engine management that is allowing this power to be made.

You can put agressive cams with big ports and high flow onto any engine. It's just that this management that the LTx and LSx engines run allow the computer to dial back the fuel and ignition for cruising/closed loop and idle/off idle. A carburetor just can't match everything that is going on.

The older computers would do fine if they are tuned properly to match but it looks like the newer units are more adjustable - or at least easier to adjust.

 

the heads perform better do to the port shape. see the "vortec" has a taller port than the gen 1 SBC now the lsx has a very tall narrow port with a specific shap to the roof as well. this allows much better breathing with out loosing much velosity(sp?) you can take a gen1 put massive ports on it and it will make just as much hp as the lsx or lt? and vortec setups but usually does this at a peak rpm. where the better shape and as mentioned deg. of the heads play big rolls in the curve, driveability and out and out power.

using a 18 deg head on a gen 1 sbc is nothing new but, from the factory is something I have never seen. this is why the lsx is the newer better toy right now.

 

i know the lsx has better port shape, tuned fairly short intake runner setup, and great management with the ECM. I know the Lsx power is more in fact due to the 15 degree valve angles and those tall ports

but LT1 heads are similar to Gen I's and i have not seen anyone running a 400whp n/a 350 here without having a HUGE cam and heads. most i've seen is like 350whp thru an auto which is pretty impressive. Thats about it.

I hope to make atleast 350whp with my AFR eliminators and decent sized cam on a 355. we'll see tho, i may do a 383. either way i'll be pissed if it dont turn the numbers it should

 

don't know? I know a 236 dur. cam has done it to the wheels. I am sure it has been done though. and I guess it comes down to alot of other little things like the specific comp. pistion ring gap. (really if you blue print the eng.s rotating the same, barrow the lt1 intake and run the heads) I don't see the rev. cooling or eng. managment making any noticable differance.

 

seems like LT1's and sbc's should make similar power... i can only hope my combo turns out well

 

My guess is part of the reason why LT1's dyno more horsepower than TPI is because of the intake manifold. The LT1 intake is a straight shot right into the heads, while the TPI takes a zigzag route thru the runners and intake manifold. Engines with MiniRams and StealthRams make just as much power as LT1's but there are so few people on this board with them.

Otherwise I dont think there is anything more special about LT1 heads than any other aftermarket SBC heads with similar flow specs.

We're doing a lot of research and development here in SoCal on how to make TPI intakes flow more air. So far we have gotten my majorly ported TPIS intake up to 310 cfm. Stock TPI intake flows 240 cfm and mine flowed 265 with minor port-matching. With the siamesed SLP runners I have this engine should be able to flow a lot of air.

Allen's made 350 RWHP thru an automatic because he has some issue that is keeping it from being stable at higher RPMs. Its either not enough spring pressure or his 3/8" pushrods are too heavy. I have a Hydra-Rev kit and 5/16" pushrods so I shouldnt have that problem.

 

Look at the LE packages that Lloyd Elliot makes, those are stock casting heads that are ported and polished, flow almost 300 and with the cam that is similar to the CC306 says 420hp to the wheels with a 58mm TB 30lb injectors and a decent tune.

 

yeah you guys have been doing some awesome stuff. Its just that when i browse the board for 1/4 miles and see ppl's combos, i expect alot more from them. Allens car made that 350whp early in the rpm range and had more in the car if the valves didnt float, i read that thread, and it was with a somewhat small 218/224 XFI cam. Thats just about the most impressive combo i've seen so far and that was with heavily siamesed TPI. I'm curious as to what happens when you do HSR or similar on that?

I've seen some superam 400+inch motors only make 400 to the wheels. which is AWESOME dont get me wrong but there are 355's doing that in the LT1 world.

LE packages are awesome stuff! AI packages are doing some good stuff as well. Something about those LT1 heads i guess. I cant wait to see how my AFR 195's work. I hope they flow as advertised, (280cfm) and i get the numbers my combo should put out.

 

Don't forget to consider the combustion chambers when comparing all these engines. The LT1's are a big improvement over the L98, and the LSX are a big improvement over the LT1. It makes a significant difference with gains in all areas-power, efficiency, ect. Also remember that an LT1 swap is a weight reduction, and an LSX swap is an even further reduction. There are some threads on here somewhere showing that the 3rd gen serpentine setups can be modified to work on an LT1 as well. LT1 swaps are getting cheaper all the time as they are so overshadowed by the LSX motors. There was an LT1 Z28 on craigslist here the other day with body damage for $1700.

 

Big thing about the LT1 heads, angle plug so it can have the spark closer to the exhaust valve for better ignition of the fuel for less waste through the exhaust.

 

well dont the aftermarket heads like brodix/dart/AFR/trick flow have the most modern chambers available and good spark plug location? i still have seen combos that should make a good 50whp more than what they are making, while ported stock head LT1's are flowing good and making GREAT power, yet an older design.

It seems hard to get a thirdgen to trap over 115 in the 1/4 mile, thats with heads/cam/intake (not TPI)...yet LT1's can do that fairly easy with a cam only cc306 or GM847 cam or so. even smaller grinds are getting 112-113mph

 

Some do, some don't.

 

I am certainly glad that I started this thread. It is very interesting to see everyone's opinion on why one is better than the other or where the "magic" is, for lack of a better term.

Can anyone else tell me why one two valve per cylinder, cam in block, pushrod V8 would be better than another?

It seems to me that the big factor coming in, over and over, is the cylinder head. So, if I've got a meaty set of heads, I ought to be able to run the same engine management system as an LTx or LSx with similar results, right? That's assuming that I can get close on the shape of the chamber and the size of the runners (volume wise) and valves. I think I can.

If not, where else is the magic needed?

 

LSx also has the advantage of 4 bolts per cylinder, freeing up more room to optimize port shape & size.

 

You can get the port volume the same but can't get the port shape of the L98 style heads as good as the LT1 heads. You can't get the combustion chamber shape as good either. There's no real need to since GM already did it for you with the vortech head. The newer engine management systems will make the old engines better but won't make them as good. The newer engines are the product many changes large and small that all add up. The LT1 (actually the LT4) is the ultimate refinement of a 50 year old engine design. The LSX is a completely modern engine design that has a quality of airflow and efficient combustion that the older engines will never match.

 

My older Buick/Olds/Pontiac setups have that advantage as well...

 

I'm not so sure...

I have some stuff that I think is very similar to the LSx design on older Buick/Olds stuff and looks to be where GM powertrain got their ideas. Good ideas that are refined a bit better today will mean that I have a little work to do. I like the combustion chamber shape and port shape/volume/flow characteristics very much of these LSx engines. That is my target to concentrate on.

What is the advantage of the fractured cap technology in the LSx engine and has anyone had problems with that yet? I'm guessing only the aluminum block versions do that and the cast iron truck blocks are normal? Does anyone know?

 

A lot of the older engines have some of it but none of them have all of it on the same engine. Olds engines have a decent combustion chamber, the intake ports are just fair, and the exhaust ports are terrible. (I have a Olds so I am qualified to criticize them) Some of the Pontiac engines have decent intake ports and chambers, all of them have poor exhaust ports, and all but the SD455 have weak lower ends. Buick engines are similar-good points and bad points. All the BOP engines suffer from a very limited choice of intake manifolds that work well. None of those engines have an intake port that is as good, or has as much potential as an LT1. Every engine is a compromise and it's a question of balance. The BOP engines are for the most part "out of balance". As in the intake ports are much better than the exhaust ports, or the crank & rods can't reliable make power in the rpm range that the motor wants to go, ect. The original gen1 small block chevy is such a superior design because no individual aspect of it is perfect but they all work well together. The newer small blocks have built upon that strength and have improvements in all areas.

Don't get me wrong- I'm not trying to discourage you from doing anything with other engines. All of them can be made to perform, and perform better than is commonly expected, and on a tight budget. But they all have one or more big deficiency compared to the more modern engines. It all depends on what your individual goals are. If the only objective is to make certain amount of power/performance within a certain limited budget then it's pretty much accepted that using a carb is the way to go, even with the newer FI engines. If your parameters are more narrowly defined such that you want to make the power with the driveability and economy benefits of FI then it becomes a lot more complicated because you need maximum efficiency out of every aspect of the engine design. Thats why modern FI engines around 350ci will make big power with really small cams around 220 @.050 and a similar old tech carb engine will need more cam and a higher rpm range to achieve similar performance.

I'm all for seeing someone do something that "isn't supposed to work" with engines that are considered to be "junk" so I say go for It! Just be sure to go in eyes wide open and know what the weak points of your combination are that need the most work, and don't expect a 40 year old engine design to do everything that and LSX will do.

 

If you have an olds, then you need to use one of my recipes...

I agree about the olds small block heads, but if you run flat tops on a 350 (or god-forbid a 403) with shaved big block "C" casting heads, you make crazy power. I do think that the big block Olds heads are far superior to LT1 hardware. I have that stuff, as well as some lighter, first run diesel blocks with plenty of meat and strong rods and crank. A cam can be had to closely match the LSx profile as well.

I have run the C heads on small blocks before with amazing results. I have not gone to the aluminum pieces yet due to budget. At this point, it's still cheaper for me to put my stuff together and buy a cam along with used LSx controls. I expect similar power.

One thing I am not up on, is the valve angle. I keep hearing about 18 degree or 15 degree valve angle (which is it, by the way?) and obviously I can't make that apply to my situation, that part is engineered beyond my control. I'm just curious as to the benefit. I see it somehow allows more lift, but is that it?

 

Standard production small blocks are 23 degrees- there are aftermarket and race heads that are 18 and 15 or 16 IIRC. Don't know what the LS motors are. "Rolling over" the valve centerline allows for a better balance between the intake and exhaust ports, and usually includes raised intake ports. It also allows for a smaller, flatter, combustion chamber with a bigger quench area. If you look at a big block Chevy head you see that they angled the intake cl to the intake side and the exhaust cl to the exhaust side. Hemi's have them laid all the way over to make the ports a "straight shot" to the chamber. Both of those engines have great airflow but poor quench and require a domed piston to get any compression at all, which interferes with the flame front. They trade one inefficiency for another. Olds heads are very good in that respect as they have a 6 degree valve angle. Unfortunately the exhaust port has to make a very big turn down to the opening/header flange surface. It also has a bad "dog-leg" shape to it, siamesed center ports, and a huge exhaust crossover. In spite of all of that they will still make really good power pretty easily. Big block heads on a small block Olds are a good combination but IIRC the Performer RPM intake is the only one that will work without welding up the top of the manifold first? Most all "old school" production V8's suffer from the exhaust ports being too low on the head. Fords are the worst. A 351C-4V head has intake ports that flow more than a square port BB chevy and exhaust ports that flow much less than any SB chevy-even though they have a lot of volume.

 

they all use this...

Piston and Connecting Rod Assembly
The pistons are cast aluminum. The pistons use 2 compression rings and a 3-piece oil control ring assembly. The piston is a low friction, lightweight design with a barrel shaped skirt. All applications use pistons with graphite-coated skirts. The piston pins are chromium steel. First design applications use a piston pin that is floating fit to the piston and press fit to the connecting rod. Second design applications use a pin that is full-floating to both the piston and connecting rod. The connecting rods are powdered metal. The connecting rods are fractured at the connecting rod journal and then machined for the proper clearance. The first design piston, pin, and connecting rod are to be serviced as an assembly.

 

There is also a company named RPM making single plane pieces As well. I'm not opposed to welding, or serious modifications to other used aluminum pieces...

 

This is an interesting thread, as I am currently weighing up which engine to go for in my GTA, as it only has a 305 atm. The LSx is a great engine, but there are plenty of hassles with fitting, and LTx are too rare here in Australia to be an option. I am currently thinking a 383 with Vortec heads and a stealth ram/turtle ram if they are out would be the way to go, probably with an LT4 hot cam.

 

If you read the engine swap sticky about the LSx and then read for literally hours about the swap in the LTx/LSx section, I don't think it's that bad, as far as hassles are concerned.

My main issue is the cost. It's a lot of money for a pushrod V8 swap. If I was swapping in a Northstar or Aurora engine, maybe, but damn!

 

You can generally get LS1/4L60E combos for about 3-3500 and have a really good foundation for an engine setup. LS1s and LS2s should be plentiful in Australia with Holden putting them in the Monaro's. And that's the beauty of the LSx based motors, more HP and better modding than the Northstars. LS2s are 400/400 right off of the assembly line I have a buddy with an LS2 (cam/exhaust only cam is a 224/228 .588 lift on a 113) in a GTO with a 6-speed running high 7's in the 1/8th daily driven car.

Although the videos below aren't of a third gen, it shows what a cam/exhaust only LS2 can do in a heavyass car like the GTO.

2006 Cammed, bolt-on GTO take off and driveby

2006 GTO vs Old School GTO

 

So you'd spend what an LS1 cost because of overhead cams, when the engine still makes less power and doesnt respond as well to mods... well now we're getting somewhere

 

Yeah the LS series engines are easy to get here, we have them in heaps of V8 Commodores and Monaros. It seems from the reading I have done that the main part of the swap isn't too bad, but everyone seems to have issues with the smaller details and getting everything working properly.

 

I would just go ahead with the swap, you won't regret it.

 

I think a twin overhead cam has the potential to go farther. Obviously, I'm not worried about stock configurations...

Again, the price is too much for me. I can get a wrecked Aurora or Cad for less than the typical LSx setup, except MAYBE for the truck configuration...

 

and what mods do they have for the Northstar or Aurora engines? none that I can find, no cams intake is like 500 bucks, tb is 200.

 

A friend back in Indiana is modding his Aurora (possible northstar short block) and is in tune with the go to guys on that. I know he can call direct to comp or crower to get cams, although the factory STS grind is plenty.

You just need imagination and ingenuity. Knowing someone with a machine shop and some imagination can be worth more than mass produced sbc parts from summit, you know?

 

But with those engines, you can't put a $500 in a cam and valve springs, $250 in a tune and have an engine putting close to 500hp at the crank down like you can the LS based engines, just look at the vids I linked up. The LS2 is 400/400 at the crank, just putting a cam and exhaust on that car has it running 7.80's in the 1/8th and still get almost 30mpg out of it. You would end up with over a grand in just the cams alone (or more) for the northstars. I know that the cams for a Cobra are close to a grand for on the shelf mass produced ones that Comp makes.

 

Again, I just don't think that throwing money around is always the answer. I have had the base circle of OHC cams ground down to increase lift. Others have had complete re-grinds to specs to increase lift, change duration etc...

Things can be done that don't fit your, "you can't build what I can on my super sbc budget," and they weren't all total disasters.

As far as the 250 dollars in the tune for the LS based engines, that is half of my point. I am trying to understand their system better so as to retrofit it to an older engine. Then I get the same tuning advantage they have.

I'm not trying to pick a fight; I do, however, REFUSE to march in step with the guys who all have the same chevy small block or LSx stuff. It's not the beat that I will follow.

 

lsx is nice but abit more expensive compared to LT1's and small blocks.

there are cam/heads setups for under 2000 bucks for LT1's that will dyno over 400whp providing you have the supporting mods, ie good exhaust/tune/tb/injectors

Thats very comparable to some of the biggest cam only LS1's. most cam heads LS1's seem to be putting down 450-460ish whp, some more,some less. So the Lt1 is only abit behind. But LS1 parts are generall more expensive and you will need a new intake like FAST 90/90 setup to make the bigger numbers..while LT1's can use stock ported units. LS1's are generally abit more expensive to, for the most part.

But you cant beat the weight savings

the only thing close is the LT4. LT1 cam cars with stock heads have hit 360whp. LT4's can make near 380whp with the right cam i'm willing to bet. they had good heads for a factory head.

 

I was referring to the LSx series.

 

yeah once you get up into the bigger inch lsx stuff, it becomes more impressive, but still parts are more expensive

 

As I've said elsewhere, I went through the process of evaluating various options for my "dream car" configuration. I knew I wanted a manual transmission, everything else was on the table. I preferred EFI. T56 being the only sane manual to consider these days, I went from there.

Option 1: Put a T56 behind my current 350. Attractive at about $1500-$2000. Power update, such as Vortec heads, RPM intake, Hot Cam, considered, would add about another $1500-$2000.

Option 2: Install a LT1/T56. In order to maintain my current power level, it would need modifications - cam, head porting, etc. In the $3000-$4000 range.

Option 3: Install a LS1/T56. Stock would have about the same power as I have now, EFI would make it more efficient, T56 & gears would make it faster. About $6000 to buy and get installed. Upgrades could come later.

As you may know, I chose #3. Admittedly, money is less of an object right now than it has been since I've had the Camaro (or any time in my life - it's a middle age/empty nest thing). The power being produced by daily-driven LSx cars is simply amazing. Almost impossible to duplicate with Gen I/II set-ups, is impossible when you factor driveability and economy into the mix.

 

I just had a new "head to head" LSx to Gen1 small block; I have to be honest, I just can't believe it.

Let's just say I am sliding toward the LSx camp...

I am a generator tech, and I drive a 1 ton van as a service truck. I drive it hard, and I drive it A LOT. For the last year my 3500 GMC has been an L31 Vortec with a 4L80E trans and 4.10 rear end. It is a stout piece of hardware, with HD emissions (no cats, just two resonators and 1 muffler) and A/C being the only option. I keep the truck loaded down heavy.

Well, a few days ago the shop gave me a Christmas Present. A 2005 GMC 3500 with an LSx engine. It has the exact same specs except the engine. I took it for a drive, and it's pretty peppy, so I was happy. I loaded everything into my new van and everyone wanted to know if it could keep up with the old van because I got a smaller engine, the L31 of course being a 350 (5.7 liter) with lots of power. I just can't believe how the new engine blew my 350 away. I mean, I drive my friend's 02 T/A and it's mean, but I never had a DIRECT comparison, with so many aligned factors.

I am a believer in LS-based power, with first hand knowledge, now.

Oh, the best part! My new engine is not the smaller 5.3 truck engine; I have a 4.8 LS engine! I just can not believe how this thing runs, pulls and drives, I AM AT A LOSS FOR WORDS....

 

Oh, and I forgot to mention, my old L31 got 10-11 mpg; my new 4.8 LS gets 14-16!!

I still just can't believe it...

 

It's a 4.8? you didn't even get the good motor....those are like putting a 305 against a 350, the 350 being the 5.3

 

Another convert. . .