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.

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.

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 ! :)

Ponyakr, I think he is talking about building a Pontiac V8 using tricks from the LS engineering playbook..

Sam

Don't think a high torque Q-jet equipped Pontiac V8 needs any LS tricks.

But, opinions differ.

Thx for the clarification. Yes, that's exactly what I mean. I cringe seeing a chevy motor in a classic Pontiac as much as anyone.

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.

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.

I think its absolutely achievable. I'm actually surprised more builds don't lean towards "efficiency". I was quite surprised with my car that it gets over 16mpg on the highway..and that is with a 466 at around 600hp, non lockup convertor,th 350 and 308 gears.

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.

"...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 ! :D

Wow ponyakr are you bitter and resentful or what?

Roylee62 you can get an old Pontiac engine to perform like an LS if you can fab up an electronic computerized engine management system like they have, design an exotic set of aluminum heads for them, and then perhaps also design some sort of short stroke/high rev crank and rods.

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.

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.

"... 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" ! :)

That's what I was thinking, lol.

Ponyakr you need to get out more often. You aren't the only old guy here :)

I'd guess I'm likely one of the very few (if any at all) on this forum that has played in the LS world, built and daily drove many of those engines in various types of cars. They are fantastic engines, they make silly power for their size and you don't have to spend a boat load of money to do it. It's very easy to see the attraction.
LS engines in other brands don't really bother me. People here refuse to face the fact that Pontiac started flurting with going corporate way back in 1971 with the SBC, and after 81 the Pontiac engine was dead. Pontiacs from that point on were chevy based, like it or not. They were putting SBC's in F-body Pontiacs until Pontiac died all together, including LS engines.

While I like Pontiacs, I'm a "GM" guy overall at heart, but enjoy other brands at the same time as well. A lot of narrow minded people in this hobby, those are the ones I find don't enjoy it as much.

I don't doubt that LS engines are more efficient than our Pontiac engines. Really, they should be as new as they are. I just don't think an LS engine belongs in a 60's-70's Pontiac or a hot rod. When I see an LS in an older car, I instantly lose interest and quit looking at the car. Anyone can go find a cheap salvage yard LS engine and stick in their Pontiac. That is the cheap and easy way out for someone who probably doesn't enjoy working on cars. If that's what you are in to, that is fine. It's just not for me. LS engines are also one of the ugliest engines ever made in my opinion. I'd much rather pop the hood and see a real Pontiac engine. They are one of the best looking engines ever made. I do know that my 50 year old 428 won't get embarrassed by one of these new cars.

We are getting off in the weeds so Ill just say this and drop it. Not like its going to change anyone's mind anyway. Whats strange is, there is only this section in the middle who gets super wrapped up in the branding thing. Because there is an even older group where hot rodding started that just hot swapped in whatever worked. I mean pickup a pre muscle era Hot Rod magazine. Its all swap in the new 331 Cadillac or 392 Hemi....


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.

I've helped on a lot of LS builds over the last decade, designing custom ground cams. I've got the chassis dyno results on most, so the feedback has helped tweak future designs.

Although they perform well with cams with intake durations @ 0.050" in the lower 200's, they perform BETTER with intake durations in the upper 220's/lower 230's. The stock cams are so small in order to keep the emissions in check.

The LS engines do not have the torque from idle to 3000'ish RPM that Pontiacs do. Pontiacs are better for lower RPM torque, LS are better for power above 3500. Almost every LS I work with has at least a 3000rpm stall speed converter - but the lock-up converters make them quite livable on the street.

LS's have a really rigid block, great flowing heads, relatively light reciprocating assembly, stable valvetrain with 1.7 (or 1.8) rocker ratios, and are designed to have EFI. The EFI system is killer, when properly tuned it can idle decently with cams designs that are too radical for carburetors (or self-learning EFI systems).

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.....:focus:

Not many others have designed, and made Stratostreak T Shirts because they were infatuated with it, I have...…..:D

https://preview.ibb.co/eHndZa/stratoback1.jpg

I don't know if I'd really get hung up on the junkyard motor deal. While yes there are some gems out there where you can find such a deal as a 6.0 LQ4 motor with a 4L80e and everything is good and koshur. Most of these junk yard motors are there for a reason though. The low mileage stuff that comes from a brand new vehicle that was crashed, is gobbled up by the salvage yards and sold to used engine resellers etc.

What is left in the local yard is you average 150-200K van motor that had 2 oil changes in 7 years. There's some people that would certainly just throw that engine in their car and hope for the best, but most people will end up having to go through that engine. All your savings is out the window at that point.

As a result it's not really a fair comparison to compare a freshly built Pontiac to a junkyard motor. Instead do the math and see what that junkyard motor is going to take to get right as well as the pontiac you have in the corner.

What you'll likely find on the budgetary side of things is the "It depends" situation. It depends on what your goals are. It depends on what you currently have and don't have,

When I was in need of making changes because I had an engine that wouldn't run on pump gas, I looked seriously at doing an LS swap. I already had an engine that was put together and in good running order, except for a set of heads and a cam setup that didn't allow the engine to work as a street car. My goal was around 500hp and reliable. In my situation, it was cheaper to do the heads and cam on my pontiac than to swap in an LS to make the same power.

If you don't have an engine on hand and you need one, the delta shifts in favor or the LS engine. Especially if you need just a basic rebuild with maybe a hotter cam. As the HP goal rises, I've found that the budgets needed start to converge again up to about 600-700hp where the Pontiac block starts to become a liability. This pushes the delta again towards the LS as the factory block can handle much more power. As your power goal starts exceeding 4 figures, up to about 1200-1500 when you're talking about an aftermarket LS block, again the budgetary issue starts to merge between the two.

My point is that the issue is far more complex than just saying, junkyard LS and profit. Each person's situation is going to be different and what route they take should be made based on their personal goals for the project.