Well i know compression dropped by 1972 which resulted in way less power. (At least thats what you read everywhere)
There is no arguing that a 1979 Pontiac 400 with almost laughable 220hp for example suffered from this. (and smog equipment crap)

But they also changed the power specifications from SAE gross to net values in 1972.

When comparing (values from automobile-catalog.com)

1.The 1971 and 1972 Cadillac Eldorado (Coupe)

both 500cui

1971: 235 / 365 hp, 410 / 535 lb-ft (SAE net / SAE gross)
1972: 235 hp, 385 lb-ft (SAE net)

2.The 1971 and 1972 Chrysler Imperial (Sedan)

both 440cui

1971: 220 / 335 hp, 350 / 460 lb-ft (SAE net / SAE gross)
1972: 225 hp, 345 lb-ft (SAE net)

3.The 1971 and 1972 Oldsmobile 442 W30 (Coupe)

both 455cui

1971: 300 / 350 hp, 410 / 460 lb-ft (SAE net / SAE gross)
1972: 300 hp, 410 lb-ft (SAE net)

Am i missing something or are these cars equaly fast/powerful despite made in 1972?
Does this mean there have been still some cars after 71 which where as powerful as in 71 and bevor?

I mean especially when considering something like the 442 W30 there is a huge price difference in 1971 and 1972 models.
So if the 1972 model is just as fast one could save a few bucks there.

 

Well given the 220hp from that 79 Trans Am with the 400 is almost as much as what the 71 Cadillac and Imperial produces (SAE net),
it almost looks like its not really laughable.

Well but im almost sure i am missing something?

 

Most engines were the same between 71 & 72. The "net" ratings that they started showing in 71 & using across the board in 72 were obtained with the engine on a dyno with all the accessories installed including exhaust, air cleaner , etc,etc, Unlike the gross ratings which used just the engine with no power robbing accessories. There is so much wrong info out there about 72s being complete slugs compared to the 71s. The 72 W30s do seem to take a price hit, they were a little more generic, losing their red fender wells, going back to just an option on a Cutlass but they still had decent cams & still had the aluminum intakes, they were still powerful cars!! Besides 72 is the only year you can prove it's a W30 without a doubt with the new for 72 vin sequences! If it has an X in the vin it has the W30 option. If I had the room I'd buy a 72 W30 in a heartbeat but I'd have to swap out the grilles for 71 pieces , I never cared for the silver grilles on 72s.

 

Oldsmobile engines are virtually identical from 1971 to 1972, so performance is also identical. This is why I don't understand why the 1972 W-30s don't get any love. They must be the Olds performance bargain of the century.

 

Thanks for your replys.

Here is a comparison between the 1979 Pontiac Trans am with the 400 Engine and the 1971 Chrysler Imperial with the 440.

Trans am: 220 hp, 320 lb-ft (SAE net)
Imperial: 220 hp, 350 lb-ft (SAE net)

Those are almost identical numbers.
(but the Imperial is SAE gross rated at 335hp and 460 lb-ft)

Even the 1980 Turbo Trans am (i find that engine quite interesting btw) delivers similar numbers with:
210 hp, 345 lb-ft (SAE net)

So is all that talk about "low power after 1971" basically just bullshit?

 

1971 Dodge Charger R/T 440/727: 305 / 370 hp, 400 / 480 lb-ft (SAE net / SAE gross)
1972 Dodge Charger Rallye 440/727: 280 hp, 375 lb-ft (SAE net)
1972 Dodge Charger SE 440/727: 280 hp, 375 lb-ft (SAE net)
1974 Dodge Charger SE 440/727: 275 hp, 375 lb-ft (SAE net)
1974 Dodge Charger Rallye 440/727: 275 hp, 375 lb-ft (SAE net)

1971 Dodge Charger R/T 440/727 3x2bbl: 330 / 385 hp, 410 / 490 lb-ft (SAE net / SAE gross)
1972 Dodge Charger Rallye 440/727 3x2bbl: 330 hp, 410 lb-ft (SAE net)

some more comparisons.

 

As has been shown above, it's mostly just a ratings thing on paper.

Back in high school I drove a 1970 Cutlass Supreme 350-4bbl rated 310 hp. I was mighty proud of that and thought it was superior to classmates cars with 200-something hp. Then I raced my friend with a 1971 Cutlass Supreme 350-4bbl, same rear gears, and I barely beat him by pulling ahead slightly at the top of 2nd gear. Now I realize that the main difference between our engines was the factory rating. Other than my 70 having a ~1.5 point higher compression ratio, the engines were the same.

Another friend had a 1972 Gran Torino CJ rated 248 hp and that car was way quicker than I expected.

Then there was a classmate who bought a Turbo Trans Am. We raced and at the start I recall seeing some lights going across his cowl intake (an optical boost gauge) then all I saw was his car in my rearview mirror. Man that TTA was slow!

 

Well seems like there are quite some deals to be had with cars made after 71.

Was that one of those 1980/1981 TTA's?
If so why was it that slow? Compared to the 1971 Imperials 440 it should not be? Almost identical SAE net ratings.
Maybe because of the turbo lag / not that linear power curve as a naturally aspirated engine?

 

introduce 1970 to the comparison, before most compression drops (at Chrysler only the 340, 440+6 & HEMI did not lose compression for '71)

and perception is blurred by experience - the "FAST" cars post 1970 were so few that many did not experience them

lots of manual transmissions and high gear ratios pre-1970 = "QUICK" VS. post '70 with automatics and 3.08s the norm = "not quick"

there is a discussion on another site about the 400 Mopar, 402 Chevy & 403 Oldsmobile: all mass produced mid-'70s engines without much street credit
their reputation would be different if any of them were even offered with a 4-speed and 3.90 gears

 

the Imperial 440 is not a performance engine - it is a 2 ton plus people mover
1970 440 single exhaust 350hp
1971 440 single exhaust 335hp (lose of compression VS. '70) 220hp net
1975 440 single exhaust 215 hp net (additional lose of compression)

 

Well of course your right, 4 speed and gear ratio makes a huge difference.
I forget to take that into account everytime when doing such comparisons.

 

Hi,

If you want a good sign of the times back then, what was the fastest production vehicle in the US in 78/79.

A 1/2 ton Dodge Truck, Little Red Express, go figure, 360 4v also no convertor due to truck emissions in most states.

Got to remember also early Fox bodies were what 220hp, even production Gran Nationals weren't much higher..

Now days all of our cars are slow compared to modern cars or trucks,, 300hp sedans,, hell my wife's Jeep V6 is rated at 285hp and scoots for a 4 door Wrangler.

Regards,

 

A lot of it has to do with modern transmissions. I bet one of our old engines, with a modern six speed and proper axle gearing could be far more driveable and would get significantly better MPG.

 

Just an FYI: The '78 Trans Am had to be dumbed down because the Chevy Boys couldn't stand to have their precious Corvette whooped.

The only '79 T/A 400s were 4-speeds. The automatics were Olds 403s.

 

Along the same lines the '86 Grand National was "rated" lower horsepower than the Corvette, which was GM's flagship performance car, but the GN would smoke the Vette.

 

71/72 were pretty much the same. 73-on got increasingly horrible, at the same time that new body platforms were getting BIGGER.

Of course actual performance went to hell.

 

An important thing to note is that the multiple geared transmissions and lower rears were not put there for power. The engines took a dump when they were introduced and on purpose. The idea is to give the engine more numerical advantage to start....so you can use a less powerful engine. Thinking your BBO would have survived in later years had overdrive come in earlier is incorrect, the crap 307 would have been right there with them. This is why we can have so much fun with a brutal powerplant and a low rear and an overdrive transmission; it's a performance combo that would not have existed on a normal passenger car.

I think power dropped with the loss of the big blocks in the mid 70s (and was dropping earlier due to emissions bullshit) and was not caught back up till 93 or so with the LT1s and similar engines.

 

Quarter mile times and HP numbers are good brag points, but overall performance is what makes a car fun to drive. Like the GN and Corvette comparison, any GN thinks they have a Corvette beat until they have to make a turn. Doesn't make it a bad car, but a Corvette is 20 times more fun to drive than a GN overall IMHO. I've never bought a car solely based on HP numbers or what it could do in the quarter-mile. Otherwise, I wouldn't own nary an Oldsmobile.

At some point, strangling existing engine platforms for emissions was the fix, until they figured out how to design lower-emission, higher efficiency engines. It's been a dance between bean counters and engineers since day one, but today's engines far and away exceed the performance of the old. And lower emissions to boot.

 

Power definitely started dropping, if not on certain specific engines. Absolutely on specific models. The entry level 1971 442 had 270 NET HP, the entry level 1972 442 had 160 NET HP. While still being the same body type.... Sure their were exceptions but the downward trend in power and or power-trains was on a roll, that bottomed out in 1975. The overall original muscle era was 1964-1974, the mandatory single catalytic converter for 1975 sealed the deal.

Exactly, 1972 W30, 1973 SD 455, 1974 SD 455, all 3 absolute beasts, all 3 right up there with the best of the pure muscle era 1964-1971. But all 3 models had a combined production of roughly 2000 cars....


Michael with regards to the 1979 Pontiac 400 4 speed Trans Am ( 6.6 T/A) it was severely underrated. Almost 97 MPH in the 1/4 mile for Car & Driver. NHRA pegged its true horsepower at up to 280. Performance backs that up. Its on par with a W31 while having a single catalytic converter. Arguably the most powerful car money could buy factory new in the states from 1975-1985.

Very special vehicle, reverse the emissions regulations and its also right up there with the best of the pure muscle era.

 

Ok, there were three events, unrelated, that happened.

From 1970 to 1971, the compression ratio was dropped for unleaded gas. This means the 1970 442 455 that was rated at 365 gross HP had as its successor a lower compression 455 that was rated at 340 gross HP.

From 1971 to 1972, the horsepower rating system was changed from gross to net. The 1971 455 that was rated at 340 gross was now rated at 270 net HP but was the same engine, with the same performance.

From 1971 to 1972, 442 went from a dedicated model with various 455s, to an appearance and handling package of various engines, including a 160 net HP 350. This 150 net HP 350 had nothing to do with the power output of a U code 442, which had precisely the same engine as a 71 442.

So, a 1970 442 is faster than other years due to higher compression than later years, and bigger displacement than previous years. I would like to see a heads up race between a 70 442 and 68 H/O. A 71 442 is slower due to lower compression. A 72 U code 442 and a 72 H/O are the same power as a 71 442. 72 442s with other engine codes are lesser due to smaller engines.

I think all that's right.

 

Mopar didn't significantly reduce compression ratios until 1972. Ditto Ford.

 

There was no "mandatory" (i.e., Government mandated/regulated/required) catalytic converter...ever. The 1980 Honda Civic 1300 could meet emissions standards without a converter...so Honda didn't install one.

There were emissions standards that were easier to meet if the vehicle had one or more converters; and as those emissions standards got more restrictive, eventually they were "impossible" to meet without one. The only reason they got a single instead of dual catalysts was GM cost-cutting. They had to warranty the things for 50K miles--which is why they produced a pellet-style converter. It was theoretically less expensive to vacuum the "old" beads out, and blow "new" beads into the same ol' shell. No welding, no clamps. Just unscrew a threaded plug, and have at it. Put the plug back in when you're done. Some vehicles required fresh beads at some pre-determined mileage. They put a "flag" over the odometer; a piece of plastic with the word "Emissions" or some-such would pop up at 30K miles, you had to go to the dealership to get new beads, and the tech would then re-set the flag. I guess it'd pop up every 30K miles and cover most of the odometer.

Real life wasn't cooperating very well. The plugs seized, the screen that kept the beads/pellets in place corroded through or broke from excess back pressure...and the shop tools required to suck and blow the beads may not have worked as well as it did in the engineering lab.

I can't tell you how many mufflers would sound like a Maraca when I'd pop them firmly with my fist. "Yup, your catalytic converter is ruined--all the beads are in your muffler." I remember seeing cars spit catalyst beads out the tailpipe.

In '75 and '76, Ford full-size cars with certain engines got a single catalytic converter. Ford pushed the exhaust from the right cylinder bank through a catalyst, while the exhaust from the left bank went out the tailpipe without. I guess that catalyzing only half the exhaust was enough to pass emissions regulations, while eliminating the possibility that those other four cylinders would be harmed by a plugged catalytic converter.

 

What engine parts were changed on the 70 to 71 Olds 442 455 that brought down the Compression Ratio ?

 

Pistons.

 

Pistons. The dish got larger to reduce the compression ratio.
That also happened on the 350 engines.

 

E vs. G heads but as mentioned most of the compression drop was due to dished pistons. CC volume was similar.

 

Could be like Ford, where they just quit machining the decks to the proper height. Don't have to change any parts, just revise the dimension on the deck-height drawing.

Now you've saved machining time, the machine tools last longer, you can cut more blocks in a shift, the company is more profitable. 'Course, you've totally screwed the quench/squish, the engine detonates or needs a heap of ignition timing or both to run decent. But at least the gas mileage is terrible.

 

Absolutely I'm familiar, no argument from me on that. The fact that there are less powerful 442s in 1972 (5 out of 7 available options) is what I am mainly touching on. Leaving the impression that the 72 is weaker even if some versions aren't. I wouldn't be surprised if this is partly why the 72 W30 is somewhat overlooked. Losing model status also didnt help.

The 270 HP 442 of 1971 went from being standard and common to being rare and special for 1972. That had to have left a mark.

Some very interesting information in your reply Schurkey. The full size Ford of 75/76 was a real eye opener.

With regards to the cat being implemented, one way or the other you were gonna be hard pressed to get a new U.S. car without it. But I understand your point that meeting the emissions requirement was mandated, not the equipment that helped to get it there.

What I was more interested in pointing out was that performance died in 1975. One of the better ways to view its impact is by looking at the Chevrolet 350, in particular the L82 as it is one of the few true performance engines that started within the transitional years prior to catalytic's, survived and started to thrive again with them before it was phased out. It was the keeper of the flame in a sense, and Chevrolet went all out to keep it healthy.

1973 250 HP ( born special in a bad time)
1974 250 HP ( performed on par with the LS4 454)
1975 205 HP ( neutered ) ( ground zero for performance 16.1 @ 87.4 MPH Car & Driver )
1976 210 HP
1977 210 HP
1978 220 HP
1979 225 HP
1980 230 HP

KW absolutely, done all the time. The 1973/1974 L82 in the Z28 was de-tuned ever so slightly so that Corvette reigned supreme. They did not mind holding back a first cousin to make the point. So you know they'll have no mercy for distant family.

Vettes are not really in our wheelhouse, as they are sports cars and not muscle per se. No denying though that very few years have they actually been bested, and its almost always a very limited production model that did it. From 1964-1988 which are my peak years of car interest. They have been outperformed a handful of times at best. I can come up with 5 likely occasions. 1987 GNX, 1979 6.6 T/A, 1974 SD 455, 1973 SD 455, and our favorite automaker Olds with the 300 HP 1972 W30.

For 1972 the best Vette was a 270 HP LS5....

 

I never owned a 71-442. Personally, I owned a 72 and a 70 442. Yes, the 70 is faster, no shocker there. What I recall in High School was that one friend had a new 78 Z28/4 speed. He took most/if not all the smog stuff off the engine, slapped a Edelbrock alum intake manifold on it and that car was absolutely fast by any standard. I recall a big race where he beat a fast 69 Camero SS396. I was shocked because that 69 SS also was a 4 speed car and it was a truly a fast car. Another friend owned a 78 TA/4 speed car and it too was very fast after stripping the smog crap off of it. The speed of those two cars still amaze me all these years later

 

I would guess the 455 in my 1972 is making 400 horse power or more
albeit the engine was from a jet boat of that vintage and then modified slightly
I thought a 1971 ram air NOT w30 442 made 340 horse power from the factory

 

Turbo lag was beyond horrible. I drove a coworkers for an afternoon and it is as described: you mash the throttle and a few seconds later those lights on the hood go on one by one. Then about 3 seconds after that things begin to happen. By then the other guy is crossing the lights at the end of the dragstrip, lol.