jpc647

No, I think some people just have different idea's of what powerful is. I have a 72 Cutlass with a 350, high rise aluminum intake, edelbrock carb, 3.33 gears in the rear. 40k mile original motor. I know I have some sort of a problem atm, but when I first bought the car, it was in perfect running order. It would peel out from a 25-30mph roll, and I still though it was a dog. It's got low end grunt, but it's nothing to write home about.

Granted I drive a 330hp RWD car as a DD, but my Cutlass is still a dog, but someone else driving it might think it's a rocket.

[QUOTE=Aceshigh;339177]I put my 1970's rebuilt 350 on a dyno and it spit out ~300hp at the crank and ~425ft lbs.
That's the ONLY way to really know what you have, to put it on a dyno.

QUOTE]

What were the specs of this rebuild? What parts, etc were used?

79MKII

When I say dog I mean dog....no way was this car going to spin the tires unless it was power braked. I floored it at about 30 mph and it accelerated so slowly that anyone in the car would never have known it was floored. My '01 grand caravan would smoke this thing! Like I said, there was no passing gear, but it still seemed really slow. My '72 was slow compared to other stock 350 olds powered cars that I've driven, but with a good tune up it would definitely do a good burnout.

455man

At 30 mph you should be in 3rd gear, so no downshifting would make a huge difference in the butt meter. My 2bbl 350 single exhaust with 176k miles has a TH400 and 2.73 gear and will spin one of the 275/60/15's easily. It has so much more potential. Set up right these cars will run just fine on the streets and high 14's on the track without taking a head off.

bkeese

And your point is?

Does not "oxides of nitrogen" = "emissions" (polutents)?

How about "pass emissions" = "regulated by new environmental rules"?

Difference is I spoke English!

79MKII

Good point about 3rd gear....wish I would have paid closer attention to make sure it was 30mph/3rd gear. When I first bought my 72 25 years ago, it had the kickdown cable disconnected too....is that a strange coincidence or is that common for some reason?

79MKII

I was reading about oldsmobile heads and found that the '71 is supposed to have a "7" head. This looks like a "5". Is there another number somewhere? The casting number matches for the '71 but not the single digit head number. (see attached picture)

MDchanic

Here is your original quote:
You state that "emissions were measured by emissions emitted / volume of gas consumed," by which you seem to mean that emissions were tabulated as a percentage of overall exhaust volume (as opposed to being tabulated by mile traveled, amount of fuel consumed, or amount of energy expended, I assume).
You then state that using more gas (getting poor fuel economy) allowed the auto makers to control emissions less stringently.
Finally, you say, "They retarded the timing and lowered the compression, thus consuming more fuel and [passed] emissions," clearly implying that their objective in retarding timing and reducing compression was to use more gasoline, thus somehow reducing their emissions.

I am setting the record straight for those readers who might actually pay attention to any of this, and making it clear that compression was decreased and timing was retarded to comply with Federal requirements to reduce oxides of nitrogen, and not because using more gasoline allowed them pass their emissions certifications.

Incidentally, measuring noxious emissions as a percentage of overall emissions would not result in a situation where there was an advantage to reducing fuel economy, as any engine of any size would emit the same percentage of controlled emissions if its overall design were the same, so the automakers could have passed emissions requirements just as easily with smaller engines as with larger ones. If what you are trying to say is that there were no fuel economy standards at that time, that is correct, and is the reason automakers chose to reduce efficiency (by lowering compression) as a way of reducing emissions, which probably resulted in more emissions overall, as the larger engines of those years (needed in order to produce power levels acceptable to the US market) produced huge volumes of pollutants, which may have had lower proportions of controlled emissions in them, but which made up for it in sheer quantity.

- Eric

ps: It has been my experience that those who accuse others of "not speaking English" have a tenuous command of the language themselves.

MDchanic

If you look, MKII, you'll see that the number you want is under the alternator bracket on that side. Look at the heads in the picture to see where the right number is located. (These are big block heads with letters, but the numbers are in the same place).





- Eric

79MKII

Got it, thanks. It's right above the block serial number. Just curious...does the "5" mean anything?

Mr Shifty Sidney

"The engine in the '71 ran perfectly. Really smooth, no smoke or noises, not even a lifter tick. It just barely moved when it was floored. Here are a few pictures I took with my cell phone....this thing isn't a 260 in disguise or something is it?"

Looks like an Edelbrock carb hiding under there. That might be your trouble. Did the car downshift when you floored it? I agree with BlackGold, my freind had a stock 50k mile 72 4dr with a 350 2bbl that ran strong! If the engine and trans are factory and in good condition than you should be able to "tuned" to make the it run strong as it did from the factory. Do not forget that changing the ratio in the rear end will make a big change in the way a car performs.

Seff

The spark plug for the 5th piston/cylinder? Doesn't fit with the position, though.

79MKII

It didn't downshift, owner said the kickdown cable was disconnected. I'm hoping I can fix that easy enough. And yes, that's an edelbrock carb for sure. I'm not familiar with them....not good? Or just not set up properly? Mine all had the stock quadrajet on them.

Diego

This is not true. ALL General Motors passenger car motors had lowered compression for 1971. Also, if you look hard for 1971 literature, you may be able to find hp ratings in gross and net. Don't quote me on this, but the 1971 W-30 was rated at 310 net hp.

Also, I quickly glanced at the attachment in a previous post regarding Olds engines and hp, and were my eyes failing me in that there was no W-30 listed? And then there was a typo for the 1969 W-30. That's one document I'm NOT right-clicking!

Mr Shifty Sidney

79MKII
I had an Edelbrock carb and did not like it, jmo. If it is just the downshift cable that should not be hard to fix. I believe on turbo 350s the downshift cable runs from the accelerator pedal out to the passenger side of the trans and 'hooks" in.

79MKII

Just ran across this old thread when I was going to buy the '71 Supreme. I ended up with another '72 Supreme nearly identical to my old one and I just wanted to say that this one is way faster than my last one. Not sure why but this one really gets up and goes. My olds one ran perfectly but just didn't have that much power. It was like that for the 22 years I had it. I'll have to look closely at this one someday and see if any engine work has ever been done to it. Nothing obvious other than edlebrock carb, air cleaner, HEI ignition and dual exhaust. Really moves out!

TexasGunner

Don't mean to raise a old post, but if I put 70's or 69 heads on my 71 engine I will have a gain in horse power? Is it a direct bolt on? Or does any modifications need to be made?

MDchanic

1. No, you will not gain any HP.
   The nominal volumes of #5, #6, and #7 heads is the same.
   You would need to change the pistons.
2. Yes, it is a direct bolt-on.
3. No, no modifications would have to be made, but no power would be gained either.

- Eric

joe_padavano

And yet, you did...

455man

I think they used a different piston from 70 to 71 and that's where the hp comes from.

joe_padavano

There's no "thinking" required. This was covered in gory detail two years ago in the early parts of this (now resurrected) thread. CR was lowered across the board in the 1971 model year due to the federal requirement for all cars to operate on low-lead gasoline. Olds did this with larger dishes in the pistons (other manufacturers changed the heads). For the 1971 model year, Olds published both the old-style gross HP numbers and the required net HP numbers, so for 1971 you can get the exact amount of HP loss due to emissions requirements and the amount lost due to the different test process. For example, the 370 HP W-30 became a 350 HP (gross) motor in 1971. The net rating was 300 HP. You can see the gross/net comparison in this page from the dealer specs brochure:

MDchanic

Actually, Joe, correct me if I'm wrong, but the reduction in compression was to reduce NOx - the unleaded thing was more of a choice by the oil companies not to stock three grades of unleaded PLUS three grades of Leaded.

- Eric

joe_padavano

OK, I will

Nope. From the GM Heritage Center website:

Here's the link:

http://history.gmheritagecenter.com/...ss_Innovations

79MKII

So they didn't lower compression ratios to cut emissions...they lowered compression ratios so they could stop using leaded gas so they could cut emissions.

BTW....I never knew that GM created leaded gas in the first place, or that they were the first automaker to design cars that could run on no-lead. They were really leading the way.....

joe_padavano

There's a big difference between saying that lower CR reduces NOx (with ANY type of fuel) and saying that lower CR allows use of unleaded gas so that catalytic converters can lower NOx.

They are also being a little creative with history. GM and Chrysler BOTH reduced CR across the board in the 1971 model year. The difference is that GM did it to all of their engines. Chrysler kept the high CR (and the need for fully-leaded fuel) in the Hemi and 440 +6 motors through the end of the 1971 model year. Those cars represented only a few percent of total 1971 production.

MDchanic

Okay, Joe, but the article you linked to was a puff piece on GM innovations through their history, written by a copy writer, and not by an engineer.

After a quick search, I cannot find a suitable source to refute your statement, so I will point out that oxides of nitrogen are known to require conditions of high heat and compression to form, and that these conditions increase with compression ratio.
I will also ask that you indulge a minor though exercise, to wit:
IF, in 1971, compression ratios were lowered to be able to use unleaded gasoline,
BUT, in 1971 (and for ten years before that), Amoco sold an unleaded high-octane gas,
AND, since at least the 1990s, gas stations around the world have sold unleaded high-octane gas, then WHY was it necessary to reduce compression in order be able to use unleaded gasoline?

- Eric

joe_padavano

I KNEW you were going to go there...

OK, first, without the lead to easily boost octane rating, unleaded gasoline required additional processing (meaning significant added cost) to be produced as a high octane unleaded. The 91-octane was then the common level for low/no-lead gas at prices comparable to leaded regular. Yes, I used the Amoco back in the day, but it cost more.

More to the point, remember when 91 octane was considered "regular"?

Back to your point, go to Google Books and look up the book "Motor City Muscle" by Mike Mueller (there are several other books with that same title). Go to page 177 for a discussion of this very topic. I'd copy/past the passage, but Google Books won't let me do that.

MDchanic

BUT, the power of the Mac will...



Unfortunately, he's not addressing the question of NOx emissions directly.
He's saying that using unleaded fuel won't reduce them, but I'm sure we agree on that.
What he's not saying is that compression ratios had to go down in order to reduce NOx nor that they did not have to go down for that reason.

He is pointing out that the Octane level of 91 (which I suspect was a RON of 91, and not and RON/MOT average of 91, so would have been closer to the current 87) was mandated as the minimum by the government, and so that number ended up being the default specification to which gasolines were made and to which engines were designed.
That still does not provide a reason why higher-octane fuels couldn't also have been made, or why higher-compression engines could not also have been designed.

I do not believe that this refutes my thesis that compression was lowered primarily in the belief that it would reduce NOx, with the secondary reason possibly being the projected decline in availability of unleaded fuel of higher octane ratings.
I would point out that the 91 octane rating was only a minimum. Refiners were free to produce gasoline of higher octane ratings, as they had in the past with leaded (and, in the case of Amoco, unleaded) gasolines, but they chose not to do so, presumably because they did not believe that there would be a market for it as the higher-compression vehicles aged out, and only low-compression vehicles remained. One would assume that this assumption by the refiners was based on the belief that low compression would be technologically mandatory indefinitely, in order for engines to comply with increasingly strict NOx emission standards. In fact, that was not the case, as attested to by my 1998 1.9L, 11:1 compression BMW, which needs 93 octane to run correctly.
It would appear that as the technology permitted higher compression ratios to produce less NOx (specifically, improved catalytic converters), refiners saw the "premium" market opening back up, and began to produce premium gas again (If I recall correctly, there were about five to ten years between the final outlawing of leaded gas and the appearance of unleaded premium).

- Eric

joe_padavano

Eric,

You've now exceeded my ability to care about this topic.

All I can say is that when I was reading car magazines in late 1970, every article talked about the lower compression ratios in the new 1971 cars so that they could run on low-lead gasoline.

MDchanic

Fair enough.

If I should come across anything definitive, one way or the other, I will post it here, just to keep everyone annoyed.

- Eric

johnnyjaws

I owned a 1970 cutlass s and that car was fast under the hood on the drivers side inner fender well there was a alaminun tag pop riveted on it from the factory and it said 350ci high output 325 hp preminum fuel only I wish I never sold that car it was gold with black vinyl top had black interior with bucket seats and center console didn't have posi in it and the manual said 2nd gear was called super gear and had a flex convertor in it I think I had a special order car ? I didn't know it at that time and when I bought it in 1978 for 900.00 bucks and it had 99000 miles on it was 19yrs old then that car also had the ss1 wheels on it and I beat that car and u couldn't hurt it . I just bought the car in my avater pic last week in ohio and its being shipped to me in ny sometime next week been sitting in that building last ten years no rust no rot at all!

79MKII

Nice buy! I had some interest in that car as well....got some photos but never acted on it. Start a thread about it and share some pics!

joe_padavano

OK, a couple of things. First, second gear in the automatic was sometimes called "super" by the marketing types. Don't read anything into that, it means as much as "rocket" as far as actual performance.

As for the pop riveted tag, Olds never installed a tag that indicated engine size or HP under the hood. The Fisher Body cowl tag is the only thing riveted to the cowl, and it did not have engine info on it. It also didn't use "pop rivets" but special large diameter rivets.

bkeese

I did a reasearch project for college English class on this subject back in the 70s. The lower compression was do to emmissions. That has probably been already stated (I didn't read all of the previous 72 responses). What probably hasn't been stated is that the Government emissions were calculated based on Parts Per Million per volumn of gas consumed. So what Detroit did was lower the compression and retarded the timing causes the engines to run like pigs and causing them to consuming more gas so they would be allowed to pollute more. Remember this was before the Japanese invasion and Detroit believed they could froce feed the American public what ever they wanted too and we would have to like it. Then came the oil embargo of 1973-4 and the sudden interest in thrifty Japanese econoboxes and Detroit couldn't give away their land yachts. My good friend (later to be my best man) sold his 1965 Mustang convertible, 4 speed, 289 Hi-Po, K-code car in perfect shape for $200. Ooch!

johnnyjaws

I say it like I seen it ! fact.

79MKII

Sounds like a custom engine builder / hot rod shop?

johnnyjaws

never thought of takeing pics back then was 2 busy having fun always loved these cars im glad to have just bought another one now that the kids are grown

johnnyjaws

I never herd of a cutlass sx till 2 day

oldsmobiledave

Dude. Use a comma or a period once in a while. Spell check is also your friend.


What the hell is a flex converter?


Finally my BS meter is pinned. Please tell us more about this special aluminum tag since this is the first ever account of such a special tag!

MDchanic

Chuckle.

Diego

Johnnyjaws, welcome to the site. Lemme explain a few things going on here so you don't think you're being picked on or being called a liar.

Many people on this board are familiar with the motors available on a Cutlass Supreme for 1970. The motor that you mention was not available on a Cutlass Supreme from the factory, and no such plate would come from the factory.

But anomalies exist. The burden of proof for that falls upon you. I'm sure you can't prove it, so those of us on the sidelines are apt to attribute it to a 30-year memory that wasn't quite accurate. Rarely do these stories pan out, but it does happen occasionally.

Considering you didn't know what a Cutlass SX was until yesterday, I'm going to go out on a limb and say that your memory is probably playing tricks on you.

Hope you don't take offense at this. We're all here to banter and learn.