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#1
12-23-2019, 02:21 AM
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Can old Pontiacs perform like LS motors?
I am amazed by the power, fuel economy and driveability of LS motors. Why can't we do this to a legacy Pontiac 400 motor, similar to an LS3 crate engine:
>300cfm heads cam: low 200s duration @.050, .550" lift, 117 LSA fuel injected Well over 1hp/c.i. and 20mpg, trans gear ratios not-withstanding. |
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#2
12-23-2019, 02:54 AM
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They are getting very good power with those LS engines. Big flowing heads with big intakes and cams not so large at all. It goes away from the Pontiac small high velocity port/mid range torque deal. We can learn from that. Folks I am dealing with doing just that on some builds.
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#3
12-23-2019, 04:23 AM
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Braggin on the LS engines is NOT the best way to win friends & influence people, on a Pontiac forum, IMO.
I don't care if they make a thousand hp, & get 50 mpg. I don't wanna see anything but a Pontiac V8 in one of the old Pontiacs that came with a Pontiac engine. If you want an LS engine, go with a body that came with an LS engine. There are LOTS of sites where they'll tell you everything you need to know about LS engines. You can find LOTS of recipes. And, there are plenty of cheap parts available for 'em. Don't know too many guys building a Pontiac engine in order to get high fuel mileage. I think most street guys do it for the low & mid range torque. And lots of street guys love to hear a good Q-jet carb kick in. BUT, as has been said on this and most other car forums, MANY times, it's your car & your money, so build it like you want it. Just don't expect ALL older Pontiac guys to like the idea of an LS engine in an old Pontiac body. No personal offense meant, at all. Merry Christmas ! 
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#4
12-23-2019, 04:34 AM
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Ponyakr, I think he is talking about building a Pontiac V8 using tricks from the LS engineering playbook..
Sam
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-- Sam Agnew Where you come from is gone; where you thought you were going to, weren't never there; and where you are ain't no good unless you can get away from it. Ministry - Jesus Built My Hotrod |
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#5
12-23-2019, 04:42 AM
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But, opinions differ. |
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#6
12-25-2019, 02:31 PM
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The Bandit Rules - Make mine with a SD-455 Engine . |
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#7
12-23-2019, 06:34 AM
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The other big variable is compression. Many late model cars of all makes run relatively high c.r.'s. 10:1 or better. This is more a function of combustion chamber design and other variables not so easy to bolt on. Also, I meant to say 20mpg with late model trans but of course ymmv with trans choice. |
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#8
12-23-2019, 11:21 AM
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I'd like to think that one could successfully argue that they borrowed some stuff from Pontiac's playbook when they created the LS1. The SBC had a 23 degree valve inclination, the new motor used 15 (Pontiac went with 14 back in 1967).
SBC ---> 4.00 x 3.48 LS1 ----> 3.898 x 3.622 350P ---> 3.875 x 3.75 Well, that *could* just be a coincidence. So let's look at the 427. BBC ---> 4.25 x 3.76 LS7 ----> 4.12 x 4.00 428P ---> 4.12 x 4.00 I'd like to see what a baby roller would do in a 350P. A well thought out grind would yield respectable mileage numbers and really breathe some life into it. That, IMO, is the biggest advantage the LS has. Yeah, they've got big flow numbers, but the cam is key. Imagine how much they'd suffer if they were forced to use a HFT with 1.5 rockers. |
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#9
12-26-2019, 01:30 PM
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#10
12-26-2019, 01:37 PM
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#11
12-23-2019, 09:47 AM
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For value you just aren't going to get there IMO. The factory heads on on the gen III motors are ridiculous compared to the old stuff. And while its a simplification, in general if you have better heads you have a faster car. It is depressing to have thousands of dollars into a vintage Pontiac and know that for less than $1000 you could go pull a used 6.0 do a cam swap and basically be making the same power. Not only that, but even with a 150,000 mile head start, the 6.0 might still outlast the old motor before it needs a rebuild.
You can certainly build vintage iron to compete, but its not going to be at the same price point. Being able to use used common factory components in place of expensive speed parts changes the game.
__________________
1967 Firebird 462 580hp/590ftlbs 1962 Pontiac Catalina Safari Swapped in Turd of an Olds 455 Owner/Creator Catfish Motorsports https://www.youtube.com/@CatfishMotorsports |
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#12
12-23-2019, 10:40 AM
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"...You can certainly build vintage iron to compete, but its not going to be at the same price point. Being able to use used common factory components in place of expensive speed parts changes the game."
You guys can rave about how great LS stuff is, as much & as long as you want to. Chevy guys have had very similar arguments for as long as I can remember. You could always buy both used & new Chevy stuff cheaper than Pontiac stuff. Lots of guys could just get a lot of the stuff they needed from friends, for free. And the sbc guys would brag about how they could wind their engine to 7 grand with no problem at all. And, of course, they'd always get better fuel mileage out of 'em. They'd brag about the Chevy engine they'd put into their GTO or Trans Am. And they'd want me to come over to their car & look under the hood, proud to show off their Chevy powered Pontiac. Whenever I saw a Chevy engine in a car that came with a Pontiac engine, I'd just turn & walk away in disgust. And when I got into drag racing, lots of guys tried to get me to run a Chevy engine. Thank God I didn't listen to 'em ! You younger guys will just have to cut us old Pontiac freeks(or farts if you prefer) a little slack. Most of us came by our dislike for Chevy engines honest. The loudmouth, arrogant, braggadocious Chevy guys forced us to be the way we are. So ya'll just go out & buy you a dirt cheap used 6.0 Chevy truck engine & build the baddest, most fuel efficient Chevy engine you can, & then stick it into any Pontiac body you have & be happy. But please do us Pontiac guys a favor. Don't come on a Pontiac forum braggin about how great it is & how much better it is than the old, out of date Pontiac stuff. WE DON'T WANNA HEAR IT. OK ??? Merry Christmas to all LS lovers, & to ya'll a good day. And Merry Christmas ! 
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#13
12-23-2019, 11:00 AM
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Honestly its the gen I SBC that I think the LS totally puts out of business. Its easier, cheaper and more reliable. The only reason to run a vintage SBC is just because you already have one. And I see your point but this isn't the same thing. There was never a 350 you could yank out of a truck at 150,000 miles, do a cam swap and make 450 HP. Or buy some used LS3 heads and make 500+. Let alone expect it to last another 100,000 miles. FWIW I just like to go fast. I have a Pontiac, an FE, and now Im building a BBC for a race car. I never really understood the whole brand loyalty thing. Its an FE that will likely be sacrificed for LS power if the 390 ever gives out. Just too expensive to justify building.
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1967 Firebird 462 580hp/590ftlbs 1962 Pontiac Catalina Safari Swapped in Turd of an Olds 455 Owner/Creator Catfish Motorsports https://www.youtube.com/@CatfishMotorsports Last edited by RocktimusPryme; 12-23-2019 at 11:07 AM. |
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#14
12-23-2019, 11:22 AM
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"... I never really understood the whole brand loyalty thing..."
No, I suppose there are a LOT of younger guys who don't understand. They just don't get it. But, there are still a few of us old codgers around, who DO get it. We were here when the first GTO hit the streets. We remember the Tri-Power 4-speed GTO's that cruised the streets of our little country towns. And we remember the Ram Air GTO's & Firebirds. We remember the 455HO's & SD455's. Naw, they weren't efficient, like the smaller, late model, FI engines. But they had soul. And they made that certain rumble of power that us young guys loved. They'd burn rubber & haul butt. And if you hopped 'em up a little you could win races. Many of us that lived thru all that can never forget, & we'll never switch. So, I'm one of the old guys who definitely does "understand the whole brand loyalty thing" !
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#15
12-23-2019, 11:42 AM
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There is a time and a place for everything. I have respect for the truly rare. But I wouldn't shed a tear for a 326 that got yanked. And by the same token I like motors in general. So I think its cool if someone tries to turbocharge a Sprint 6 or something. I even thought the Supra engine in the Firebird that popped up a while ago was a neat project. Back to the topic, I think the roller is a big part of it, but I would still circle back to the heads. Vortec 350s got roller cams. Hell they even have better heads than other factory sbcs, but it still a poor comparison to a mild built 5.3 in most cases. As I said earlier, there are some bad Pontiacs on here. No doubt. Some that have even been done on a budget. But mostly you are still going to have more money into them. Sometimes by a lot, my motor for instance. And as a total package it can get depressing. What I mean by that is you can yank the whole drivetrain from some junk van. Have a 6 liter and a 4l80E. Do a cam swap. Now you have a pretty stout motor, a tough OD transmission, and you can run a real rear gear that is highway friendly because of the OD. For what? $2500? You can look down your nose at someone for taking the easy way out, but that's the only real argument against it.
__________________
1967 Firebird 462 580hp/590ftlbs 1962 Pontiac Catalina Safari Swapped in Turd of an Olds 455 Owner/Creator Catfish Motorsports https://www.youtube.com/@CatfishMotorsports |
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#16
12-23-2019, 11:57 AM
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First of all, a whole bunch of misconceptions on both sides. SBC and LS engine are not even close in engineering or origin.
SBC started out in 1955 made until 1997 in cars, and even later in trucks. Chevy division designed, same as the Stratostreak Pontiac design, or the rocket olds, design. Clearly a division designed engine that was one of the cheapest to make designs, and why it was vaulted to the only V8 left in the corporate stable until the unveiling of the LS. LS engine was designed by corporate engineers of GM Powertrain division, GM gave the new engineering over to not a brand of car, but to a division like the Hydramatic division was to transmissions for close to 50 years. One division that oversaw transmission production for nearly 50 years, I never have seen people arguing over which automatic transmission is better, because the same corporate division made all of them. So in roughly 1992 GM combines Hydramatic and the corporate engine building under one umbrella, GM Powertrain. Cadillac, buick and chevy get their engines from GM Powertrain, there are no more chevy engines, just corporate GM. GMP engineers took all of the best design features of all the former GM designs, and a few from competitors, and incorporated them all into a clean sheet of paper design. There is buick, cadillac, chevy, olds and Pontiac engineering designed into that engine, as well as some ford in there, not sure if chrysler got any credit or not. All the latest and greatest is really not just that, it's proven ideas that work. Now GMP has done the same thing for all their engines, not just the V8 platform. Now, can the Stratostreak use some of the same engineering ideas to be more efficient? It surely can, current aluminum heads use the LS style combustion chamber, but you can repackage bits and pieces of LS technology, but without redesigning the whole engine you can't repackage everything, GM has years of design into the LS engine, and millions upon millions of dollars into it's design. A small group of enthusiasts can copy some off the stuff, but all of the stuff is what makes the LS engine a whole package. Hey, for a 70 plus year old design it did well, for many years, it's been adapted and crutched further than other designs have, so it was a great feat of engineering to begin with. I love the Stratostreak design, I won many a battle over other brands with it. I worked harder, spent more money, but I was brand loyal to it, and still am. I do own a 2005 GTO with an LS2 in it and I don't feel I betrayed my loyalty to the Pontiac Stratostreak because I own it, It ISN"T a chevy engine, it is a GM manufactured engine with input from all the former divisions designs, so there is Pontiac design in there too.....  Not many others have designed, and made Stratostreak T Shirts because they were infatuated with it, I have...….. 
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Brad Yost 1973 T/A (SOLD) 2005 GTO 1984 Grand Prix 100% Pontiacs in my driveway!!! What's in your driveway? If you don't take some of the RACETRACK home with you, Ya got cheated   
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#17
12-24-2019, 07:05 PM
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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. Last edited by LostHighway; 12-24-2019 at 07:27 PM. |
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#18
12-24-2019, 07:47 PM
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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".
__________________
Brad Yost 1973 T/A (SOLD) 2005 GTO 1984 Grand Prix 100% Pontiacs in my driveway!!! What's in your driveway? If you don't take some of the RACETRACK home with you, Ya got cheated
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#19
12-23-2019, 10:37 AM
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 466 Mike Voycey shortblock, 310cfm SD KRE heads, SD "OF 2.0 cam", torker 2 373 gears 3200 Continental Convertor best et 10.679/127.5/1.533 60ft 308 gears best et 10.76/125.64/1.5471 |
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#20
12-23-2019, 10:38 AM
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I think you can say that the technology is there to build a Pontiac motor with good performance and the driveability/reliability of a LS motor- but it will be very hard to match the power. The LS motor has 40 years of technology advancement (1956 vs 1997) so it’s hard to expect them to be equal. Similar to expecting a flathead to perform like a 389. It can be very good, but not equal.
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