[ta man]

I have a friend who is in his 20's and has done 5 or 6 high quality LS swaps into 2 mid 80's Monte Carlos, his Dad's 70 Monte Carlo, a mid 70's Chev pickup and currently a former 10 second S 10 bracket truck.
His 87 Monte Carlo is a pretty cool car..and runs 11.2 ..well thought out build, stock 6.0 bottom ..slightly work stock heads..new valve springs and roller cam...its interesting the cam is very similiar to what I run ..mild duration and around .650 lift. Engine is converted to traditional intake and carb setup.
That being said I appreciate the work and the knowledge that he has achieved but for myself I'm purest when it comes to my own Pontiacs and also admit I'm a Pontiac engine snob at car shows or the dragstrip..I wont even look at a classic Pontiac that has been swapped.

[Lee]

Originally Posted by pastry_chef

So exactly where is the imaginary TQ / HP barrier line? I see that HP and TQ both coexist at all RPM.
For best performance optimize power at the RPM where the engine spends most of its time. Giving up power below 3300 is fine if you have a 3500 stall converter.

5,252 RPM


And yes, they DO coexist - put people fixate on a certain peak HP, and do not pay any attention to what is going on below that peak. Or after it.

Several years ago, I was asked to help with an LS street/strip truck. It was 440+ cid, MAST heads, lots of good parts. It had an HR that was around 250/258. It put well over 500hp to the wheels, but it was rather soft off the line.

I had another cam ground for him, a 236/270 with similar lift. Peak HP was virtually the same (new cam was maybe 4hp higher). But, his midrange (starting where his converter stalled) got a HUGE boost. The owner had to learn to tune his Cal-Tracs, as he was then blowing the tires away.

If the only thing being looked at was peak HP, then those two cams would be considered equal. But they performed WAY differently.

[JLMounce]

Originally Posted by ta man

I have a friend who is in his 20's and has done 5 or 6 high quality LS swaps into 2 mid 80's Monte Carlos, his Dad's 70 Monte Carlo, a mid 70's Chev pickup and currently a former 10 second S 10 bracket truck.
His 87 Monte Carlo is a pretty cool car..and runs 11.2 ..well thought out build, stock 6.0 bottom ..slightly work stock heads..new valve springs and roller cam...its interesting the cam is very similiar to what I run ..mild duration and around .650 lift. Engine is converted to traditional intake and carb setup.
That being said I appreciate the work and the knowledge that he has achieved but for myself I'm purest when it comes to my own Pontiacs and also admit I'm a Pontiac engine snob at car shows or the dragstrip..I wont even look at a classic Pontiac that has been swapped.

Interesting you bring that up. There's a few Pontiac's around my area that nice cars, but shot with either an LS or traditional SBC.

I'm a purist, but also a realist and understand "not my car, not my money" so I don't really pick on people that don't have a Pontiac between the rails. I do typically ask though and almost universally I get some sort of answer that is also an excuse.

My favorite is from a guy that has an LS GTO that's setup as a pro-street / strip car. Real nice example. When I asked if it was Pontiac powered he hesitated and replied with "Well GM put LS engines in the GTO in the 2000's"

There's pride in having a bonafide Pontiac engine in your Pontiac. People know it, even if doing so wasn't in the cards for them.

[Gator67]

My pro-touring '70 Formula will be powered by an aluminum IAII (fuel injected, modern fuel delivery system, etc). Most of my pro-touring acquaintances think I'm crazy, but I'm going to give it a shot. I figure if I'm not happy with the engine, and I love the car otherwise, I can always replace it with something like an LS7.

The plan all along has been to build a 535 (and I've even considered 4.65 stroke for 552ci), but the closer we get, the more I think about whether shorter stroke would be significantly better for reliability/durability.

[Steve C.]

Jim Hand did a technical article regarding the relationship between cylinder pressure, compression and detonation.

From it... "If you were waiting for me to tell you what CR is optimum but "safe" for you, neither I nor anyone on this planet can tell you what is safe."

The article was intended to provide some knowledge only to help select the optimum CR based on fundamentals.

And further he stated.... "Each case is different in that different quality gas is available, the vehicles are of different weight and have different transmissions and gears, different cams are used, the chambers are prepared differently, and so it goes."

Are today's LS motors capable of sustaining much higher compression on much lower octane fuel apples-to-apples with the design of a older Pontiac ?


.

[JLMounce]

Originally Posted by Steve C.

Jim Hand did a technical article regarding the relationship between cylinder pressure, compression and detonation.

From it... "If you were waiting for me to tell you what CR is optimum but "safe" for you, neither I nor anyone on this planet can tell you what is safe."

The article was intended to provide some knowledge only to help select the optimum CR based on fundamentals.

And further he stated.... "Each case is different in that different quality gas is available, the vehicles are of different weight and have different transmissions and gears, different cams are used, the chambers are prepared differently, and so it goes."

Are today's LS motors capable of sustaining much higher compression on much lower octane fuel apples-to-apples with the design of a older Pontiac ?


.

Yes and no. The standard LS3 found in your garden variety corvette is advertised at 10.7:1 compression. That's on an all aluminum engine with modern heads. The engine management system is also helping here with the knock sensors, so while the engine does live on pump gas, there may be times that timing is being pulled for various reasons.

If we equate that back to the Pontiac engine, people can and do run those types of compression ratios with the modern head offerings. Some have claimed to be able to do so using factory style iron heads.

The big advantage is in that engine management system. Most of the Pontiac engines found in this section of the forum don't have the ability to pull timing based on a knock sensor. Many (as evidence by the ongoing threads here and in the heating/cooling section) struggle to keep engines cool to begin with. And so it's simply easier for that LS to cope with modern fuels with higher compression.

In the LT line of engines that no employs variable cam timing, you've got the added benefit of being able to retard or advance the cam to build or relieve cylinder pressure to work with higher static compression ratios.

If you look at the Ford Coyote motor as well as many other modern engines, they've also employed piston oil squirters to help cool the pistons in order to cope with higher compression and available pump gas. In the case of the coyote motor it runs an advertised 11:1 compression, to which people also routinely add 10-12 pounds of boost to.

What that tells me at least is that heat management is key. Get the heat out of the cylinder and off the piston. We also know burning the charge as quickly as possible helps.

We already have much of what's needed in the aftermarket to accomplish that. I'm sure an intuitive machinist could probably figure out an oil squirter in the block.

How much will a 455 with at 11:1 compression with a 300CFM head and a cam around 235* @50 make? How efficient would it be with a modern overdrive transmission, proper converter, proper tuning and modest gearing?

[HWYSTR455]

One thing on newer performance engine is that the engine management 'manages' the 'tune' in relation to perceived det by the sensors. Yes, they have higher SCRs, but that doesn't mean they run an aggressive 'tune' to take advantage of available performance. Most of the time, they don't. Some of that is for advertising, the number provided by manufacturers, and means very little in real life situations.

Thing with SCR isn't really that you make more power, but that they operate more efficiently at lower RPMs with higher SCR. That's the big advantage. And that you can use a more efficient cam profile. As an example of the effect of HP on increase of SCR, going from 10:1 to 11:1 gains you a meager 1.5% HP. On a 500HP engine, that 7.5hp. Is that worth the risk of dancing with det? Maybe, because the total gain of HP is only part of the story, but it still is a basis for calculating risk.

General rule of thumb for SCR when adding/using aluminum heads is there is a theoretical loss of SCR by 1 point. It's not a loss of SCR, technically it's a loss of thermal dynamics, you make up for it by going an additional point. So when you look at a new car's engine and say it has 10.7 SCR, that's comparable to an iron head engine of 9.7 (theoretically). So really, there is no 'running higher SCRs' in new engines.

I was planning my current build a few years ago, seriously looked at going the LS route, and wanted to. Couldn't afford to do it the way I wanted, so dropped back and punted with refreshing the engine that was in it (461) and added some stuff like port EFI, etc. Looked at crate LSs, and building one the way I wanted, both were too expensive for my blood. I would have done the LS specific ECU/ECM from Holley, Dominator LS I think it was called at the time, had trans control was the biggest reason.

VVT is cool, but it really limits you to OE programming, and increases the cost of the build in parts. Heat management is a good thing, but the cost of returns makes it difficult to justify in a 'hobby car' engine build.

Thermal coatings on piston tops & skirts, rods, and other areas is not cheap. And what will that provide you? A few HP yes, but better efficiency is the real benefit. To recoup the costs, you would have to drive the car like 50k miles probably.

Anyway, point is that it's a good thing to apply modern tech to 'hobby cars' up to a point, after that, it's really just a wow-factor, and throwing money away.

.

[JSchmitz]

Reverse coolant flow is another big difference to me. Send the coolant to the heads first. Hopefully I didn't miss someone bringing this up. Lots for an A.D.D. guy to read here. Lol!

I have a buddy that used to brag about running 87 octane in his SBC Camaro with no problem/ping. One day he was talking about it in his garage. I asked him if he ever looked at his spark plugs with a magnifying glass. We pulled one out and had a look. Covered with aluminum particles. He runs 93 octane now.

[69MaizBird]

JW makes an ultra bell that bolts to a BOP a sbc and an ls.
It's the same part. Fits all 3.
I am not sure but with a spacer for the flex I believe the ls motors will bolt right to a BOP th350 or 400 in stock form.

LS engineers did not do this by accident imo.

That said....
I have a 505 and a 535 that cost alot to put in service and keep in service.
The turbo LS I have costs less than half that and will give more peak hp.
For the record the LS is going in my kids Camaro because the Camaro can't keep up with the Pontiacs I have lol.

[LostHighway]

Personally and I mean, very personally.. I think LS engines are a sad representation of how this country has gone downhill. LS engines to me are nothing but the end result of years of cut throat corporatism and global economics that has ruined choice for the American consumer. Thinking back on past generations and how they had a plethora of options and engine choices to choose from on any given platform- to how it is now, certainly makes me feel like we have lost. Sure you can now buy an IMPORT to make up the difference, and you might have to because you sure don't have a new Pontiac or Oldsmobile etc. to consider. If you think that's a stretch and I'm overlooking the technological aspect of the LS engine, then please enlighten me on how we are better off without these companies and how I should be happy with just an LS. The technology would in my opinion be there regardless, if the company were still alive making vehicles and engines. This company was scrapped for numerous reasons, but the ultimate reason was to appease sales in China using the Buick platforms because they sell very well over there. So next time you see a Buick, just remember that there is no more Trans-Am because the Chinese needed a Buick. The cold hard truth is the LS engine is a generic engine, multifaceted from a lot of different engine designs, combined to suit many different platforms. I do not find any individuality or character in these engines. When I see an LS swap in a classic, I instantly stop looking at the rest of the car. Its like looking at a stuffed mount Bear or Lion at Bass Pro or Cabellas. Sure it looks amazing but the soul is gone. IF the owner is near I do express my feelings in a polite and constructive manner if they ask. I'd rather open a door than have a door slammed in my face. Im not rude about it. Anyway...

So how do you make your Pontiac run like an LS? You don't! You make it run like a Pontiac and leave them feeling small, just like I feel when I know if I want a hot new GM car, Im stuck with a no low end TQ LS.

But if there is someone out there considering spending the money to make a Pontiac engine modern... Please consider the controlling side of the engine you are building as well as the mechanical side. Being a current tech for General Motors, I can give you a couple ideas. Most of the "trick" in these engines is in the EFI and timing control system that operates it. Variable valve timing done by a solenoid in the nose of the cam which uses oil flow to advance or retard cam timing as much as 60 degrees on demand. A coil on plug system to further dial in individual cylinder firing, giving more dwell and a hotter spark which aids in a more complete combustion event. A crank reluctor wheel will need to be added to sense crank speed differences in cylinder to cylinder timing. This will be needed to dial in perfect timing operation. Next you have to figure out a way to make the Pontiac block reverse flow cooling friendly. You will also have to add in a couple extra coolant temp sensors to monitor everything. You want to have an ECU thats extremely capable and tuner friendly. Mechanically you need a light block thats very strong. That alone is a tough one to crack but if you got the money, Im pretty sure there are some aluminum Pontiac blocks to be had. As far as heads are concerned, a fast burn chamber to squish and direct the fuel and air mix to the spark plug area allowing for more complete burn and better flame propagation is a must.... and I suggest using KRE or Edelbrock over the open chamber Pontiac stuff.

I could go on and on, but the more time I spend on this the more I am glad Im not doing it. I think it would be far better to smoke an LS with a carb and iron Pontiac heads. ALL old school! lol Merry Christmas my Pontiac brothers and sisters.

[Sirrotica]

Originally Posted by LostHighway

Personally and I mean, very personally.. I think LS engines are a sad representation of how this country has gone downhill. LS engines to me are nothing but the end result of years of cut throat corporatism and global economics that has ruined choice for the American consumer. Thinking back on past generations and how they had a plethora of options and engine choices to choose from on any given platform- to how it is now, certainly makes me feel like we have lost. Sure you can now buy an IMPORT to make up the difference, and you might have to because you sure don't have a new Pontiac or Oldsmobile etc. to consider. If you think that's a stretch and I'm overlooking the technological aspect of the LS engine, then please enlighten me on how we are better off without these companies and how I should be happy with just an LS. The technology would in my opinion be there regardless, if the company were still alive making vehicles and engines. This company was scrapped for numerous reasons, but the ultimate reason was to appease sales in China using the Buick platforms because they sale very well over there. So next time you see a Buick, just remember that there is no more Trans-Am because the Chinese needed a Buick. The cold hard truth is the LS engine is a generic engine, multifaceted from a lot of different engine designs, combined to suit many different platforms. I do not find any individuality or character in these engines. When I see an LS swap in a classic, I instantly stop looking at the rest of the car. Its like looking at a stuffed mount Bear or Lion at Bass Pro or Cabellas. Sure it looks amazing but the soul is gone. IF the owner is near I do express my feelings in a polite and constructive manner if they ask. I'd rather open a door than have a door slammed in my face. Im not rude about it. Anyway...

So how do you make your Pontiac run like an LS? You don't! You make it run like a Pontiac and leave them feeling small, just like I feel when I know if I want a hot new GM car, Im stuck with an no low end TQ LS.

But if there is someone out there considering spending the money to make a Pontiac engine modern... Please consider the controlling side of the engine you are building as well as the mechanical side. Being a current tech for General Motors, I can give you a couple ideas. Most of the "trick" in these engines is in the EFI and timing control system that operates it. Variable valve timing done by a solenoid in the nose of the cam which uses oil flow to advance or retard cam timing as much as 60 degrees on demand. A coil on plug system to further dial in individual cylinder firing, giving more dwell and a hotter spark which aids in a more complete combustion event. A crank reluctor wheel will need to be added to sense crank speed differences in cylinder to cylinder timing. This will be needed to dial in perfect timing operation. Next you have to figure out a way to make the Pontiac block reverse flow cooling friendly. You will also have to add in a couple extra coolant temp sensors to monitor everything. You want to have an ECU thats extremely capable and tuner friendly. Mechanically you need a light block thats very strong. That alone is a tough one to crack but if you got the money, Im pretty sure there are some aluminum Pontiac blocks to be had. As far as heads are concerned, a fast burn chamber to squish and direct the fuel and air mix to the spark plug area allowing for more complete burn and better flame propagation is a must.... and I suggest using KRE or Edelbrock over the open chamber Pontiac stuff.

I could go on and on, but the more time I spend on this the more I am glad Im not doing it. lol Merry Christmas my Pontiac brothers and sisters.

There you have it in a nutshell. Yes it can be done, to a certain degree on the Stratostreak engines. It isn't going to be cheap? Nope it won't be cheap, or easy. You had better know your way around machine shop, be a pretty fair fabricator, and know how to adapt the electronic management system that GM uses, or find an aftermarket system that would be suitable.

The variable valvetrain adaption, or fabrication from scratch is going to be a major hurdle though, as well as a load sensing system to run it. All good points about the reluctor system to have accurate timing for the single coil per cylinder system, and accurate timing. Pretty easy too see why no one I'm aware of has taken the rather complicated EC GM system and retrofitted it to the original Stratostreak engine.

Chevy/GMP kind of did it to the last SBC engines, however they still used a distributor, instead of the single coil per cylinder system (Duraspark). They have a helluva lot more technology at their disposal than the average Pontiac enthusiast does too......……... They never did any VVT on the SBC that I'm aware of, it didn't come to most GM engines until roughly 2007. I can tell you that the last 1997 350 CI SBC (owned a 1997 T/A) didn't even compare closely to the 1998 LS1.

Maybe no one here realizes that there are chevy holdouts too, that are mad GM quit using the SBC as the V8 in chevy cars. Some chevy guys do know that GMP designed the LS engines, and not chevy. You don't often hear that coming from the chevy camp, but there are a few out there.

The poster makes a good analogy in his reply, the stuffed mounted game head, without the soul of the animal, is a good demonstrative tool. Remember one of Pontiacs last advertising campaigns was, "Fuel For The Soul".

[i82much]

this is like a forum for p-51 mustang owners asking what they can do to keep up with an f-16. you can’t! fill your pontiac up with gas, go burn rubber, and forget about it!

[Dragncar]

I tried to sell my 73 400 std filled, splayed cap block and KRE high Ports here and at our drag strip. I had them down to 1250 for the block, 1250$ for the rotating assembly and 2200$ for the heads and Victor. No takers here and one guy at our track with a 64 GTO came very close to buying it, passed.
They put either a BBC or LS in the 64 GTO. This next drag season I am going to hunt that car down like a animal and embarrass them with a "real Pontiac in a Pontiac". They will not have the slightest chance and I will let them know before I do it and after I clean their clock.
They will deserve it IMO. I can not help it, it offends me. They ruined the car and I will ruin their day.

[slowbird]

I know little about LS engines but don't they make 500-550hp with only low to mid 230 duration at .050 on the intake with engines smaller than 400ci? If that's true can a Pontiac 400 make 550hp with that small of a cam?

[Formulas]

I test drove a new stick 2006 GTO with the obvious LS. based engine I did not take it to redline and speed shift it but I was soooo not impressed with the power and driving experience

Set me in a stock 4bbl stick 1966 GTO and try to knock that grin off my face. A whole different experience

I did not buy that 2006 GTO and easily could have

[Steve C.]

Gen III (3) LS 500+ Horsepower NA Street-Racer Buildup

The engine tested here used the aftermarket components shown in this chapter, but engines with stock short-blocks have made similar power. The key components to make this power include the GMPP CNC-ported cylinder heads (which yield a 10.5:1 compression ratio), the GMPP Showroom Stock camshaft or similar aftermarket cam (less than 0.600 inch lift), 1- 3/4- inch primary long-tube headers, 38-lb/hr injectors, F.A.S.T. controller, and open-element air cleaner. Increasing the compression to 12:1 would increase the horsepower curve about 20 to 30 hp over the last 1/3 of the power curve, but you’d need to run 100 octane gas to prevent the engine from detonating itself to death.

https://www.lsenginediy.com/gen-iii-...racer-buildup/

Information provided in this post does not represent a product endorsemet


.

[Skip Fix]

"Are today's LS motors capable of sustaining much higher compression on much lower octane fuel apples-to-apples with the design of a older Pontiac ? " My wife's 2002 5.3 LS Avalanche rattles on 87 octane when pulling a horse trailer-and it has a knock sensor that should adjust timing.

"I test drove a new stick 2006 GTO with the obvious LS. based engine I did not take it to redline and speed shift it but I was soooo not impressed with the power and driving experience ". My hard core Pontiac buddy(he has 30 classic cars most Pontiacs) let me drive his '05 and it sure hooked me. My 2004 auto with less HP and just a computer tune runs 13s, when it hits second it better be pointed straight. Something not to many stock old Pontiacs do. My 6.2 2015 truck has way more pulling power than my '97 350 truck, and way better gas mileage.

That said a classic Pontiac (or even a Chevy) needs a classic motor in it. Remember not that long ago lots of SBC TPI swaps-look out of place now. I think LS swaps will at some point also. But a classic muscle car with a classic motor never will.

[67gtospud]

Originally Posted by slowbird

I know little about LS engines but don't they make 500-550hp with only low to mid 230 duration at .050 on the intake with engines smaller than 400ci? If that's true can a Pontiac 400 make 550hp with that small of a cam?

They need a pretty decent cam and a lot of lift to be in the 500hp range on the stock heads with no port work.

A handful of my friends have the new GTOs and Camaros. And I've swapped cars for a day with a couple of them. The new LS cars are fun for awhile, whereas our old pontiac powered cars are fun for a lifetime. Their cars may have been faster than my my 400 pontiac but when they got done driving my car they were in awe of the shear torque over their ls2 and ls3 cars. One of my friends actually just sold his ls2 GTO and is on the hunt for a 68-70 GTO lol.

[pastry_chef]

Originally Posted by Lee

people fixate on a certain peak HP, and do not pay any attention to what is going on below that peak. Or after it.

Agree.
Most people don't obtain an admirable result and rightly don't deserve one.

I'm sure many logs and programs can display an RPM histogram to indicate time spent at RPM ranges. John Lingenfelter would say optimize power at the shift recovery point.

[Sirrotica]

Originally Posted by Formulas

I test drove a new stick 2006 GTO with the obvious LS. based engine I did not take it to redline and speed shift it but I was soooo not impressed with the power and driving experience

Set me in a stock 4bbl stick 1966 GTO and try to knock that grin off my face. A whole different experience

I did not buy that 2006 GTO and easily could have

Well, in 2006 I bought my first new car ever, a 2005 leftover GTO, the car on a test drive, was not anywhere impressive as most older GTOs (OWNED a dozen over the years, from stock, to totally hot rodded). Because of the vehicle management system the LS GTOs are very linear and apply power like an electric motor does.

Now if you turn off the traction control and bring the engine up against the convertor and hammer the gas, you better be a pretty good wheelman to keep it straight. The 400 HP is there, it's just tamed down by the management systems. A tune will gain 20-50 more HP. Not to mention the tires on a 2004-2006 GTO are light years ahead of bias ply tires we had on the old GTOs. So if it seems slower, it's because of the management systems, watch the speedometer, because it's really deceiving on how fast you're really going. 0 to 100 is pretty damn fast in my GTO, because of the quiet, and better suspension, it's deceiving. The LS2 GTOs were 0-60 in 5 seconds flat in stock form, with either transmission.

To match the power I had one 76 T/A with a 455 ported cast heads, headers, and a really mild street cam (268 advertised duration) that would have been probably just about even. With about 90 more cubes, and yes a bunch more low end torque.

It's apples to oranges, but that T/A would be a real close match to my 05 GTO. GTO averages 20 MPG, T/A would get 16 when I checked it. Reworked Q Jet on a 76 cast iron manifold.

The LS engines DON'T have all the raw low end torque that a Stratostreak engine has, but there are other ways to get to the same end result. Too bad you passed on the 06 GTO, they are pretty great cars, mine is just under 140,000 miles with a water pump replacement since new.....