Old Cars True HP Ratings explained! N* vs Cad 500

[Ultra Slow]

This is a post that I got carried away with, but contains some good info for guys that did not know that muscle cars of the 60-70s, might actually have less power than the northstar they drive. It has to do with a comparison of the 400HP cadillac 500 Vs a Northstar, and why the 400HP is an overrated power rating.

"This is an interesting and great topic I say this because I have lived just this. I will explain as best as I know below and give you some examples of what changed over the years in cars HP#'s. I have owned pretty much the mentiond cars, 70 Eldo,.. but not the SLS... a couple of STSs instead along with a list of classic cars that I wount even go in to.... I will tell you without a shadow of a doubt, The STS will kick the bejesus out of the original 70 eldo.... no ifs, ands, buts, or, ors. The 70 eldo is not slow for what it is, and for this post, lets not even bring up the weight differences of an SLS/70 eldo, as its not the major factor on this example.

I think Katshot pretty much told the main reason, and this is why I dont want to mention weight factors....... Cars before 1972 were WAY overrated on HP. It was a "gross" rating and was used as a big selling point of cars, and it still has a serious effect today on the values and misunderstood performace of 60's and early 70's muscle cars.. Insurance in those days, like today, was priced with how much HP your car had. With some political influence and as a way to standardise the HP ratings, along with helping insurance rates for new cars buyers, a new way of rating cars HP came about in 1972. This is not to be confused with the fact that some engines did lose actual power because of lower compression. This all happened right about the same time. It is also not to be confused that power was lost in 1974 and later with the first generation of Catalytic Converters on 74 and newer gas powered passenger cars. It was a tough time, and all this stuff went into effect, but the HP ratings we are talking about here are a totally seperate issue.

Here is a perfect example if you are confused....I am not comparing this to a cadillac, but it transfers just the same to show HP ratings drop from 1971 ratings to 1972.... A 1971 LS5 454 corvette rated at the 1971 specs had 365HP.. In 1972 it had 270HP..... What was changed.????...ABSOLUTLY NOTHING! Same everything!.. Just by the way the HP was rated starting in 1972 it lost 95 HP. Many high compression engines were dropped in 1971 as I mentioned above, but this particular example is a low compression motor and carried on for years after. The 71 LS5 365HP was the low end Big Block.... This low compression big block LS5 stayed the same way up until 1974 when the big block was dropped in the corvette, but kept in cars/trucks with the added Catylitic Converter, to be about 200HP... The motor really did lose about 70HP from the first generation catylitic converter, but the 71-72 ratings change lost more power on paper than the emmissions did in actuality.

This even gets better..... The FASTEST stock, right off the floor corvette to its date, less some ZL1, L88 or way rare factory race car, was th 1973 454... Why???? First to have radial tires, so it hooked up and moved! The 1973 corvette, with 270HP will dust the MEGA overrated 1967 435HP tri power corvette, mainly due to traction, but the HP is not really that much different either when you convert the ratings post 71. We are looking at the 67 having, in actuality, roughly 300HP in todays ratings...the 73 having 270HP in todays ratings as it was rated 1972 and later and that is the same as todays ratings. When you add in the always "hush hush and never important" increased torque from the larger 454 over the 427, the 1973 is simply a bit faster, even taking the traction factor out. Dont try and tell this to the magazine preachers, or an uneducated mid- year corvette die hard, as they will think you are crazy, but its true. The real car guys understand this, but there are so many that you would think know, but dont.

As I mentioned above, if you took the 67 435HP car and rated in 1972, it would have about 300HP in todays world... Now dont be fooled as it gets even worse... thats not 300RWHP... Its flywheel... No US car has ever been rated at the rear wheel, unless its an independent rating... Take out the driveline loss on that 1967 435HP corvette, and go by the many dynos I have seen on those cars in actual stock form and you get about 230HP to the ground. Given that... Take an STS against a factory 1967 435 corvette.... Whos faster... In reality, if the 67 has radials, its close to about 60 then the STS will win. Been there, done this. You might not believe this, but using an "original" 67 425HP VS a Northstar STS, its true. You might read some mag article where some 67 classic corvette clocked off a 12:50 or something like that, but keep in mind that there are not too many restored corvettes that go back 100% the way they were built back then and usually have a little power added to them on rebuilds through mods. I lived that era, and I can tell you that the tales get taller as time goes on about how fast 60's muscle cars were in stock form. Most knowledgable people realise that the cars 60's/70's cars were fast in their day, and that day is unfortunatly gone.. In todays world an original 67 435HP corvette is not that fast compared to its legend. It really dynos to the ground about the same as an STS, of which on an STS 230-245 is not unusual to see the ground....FWHP in the STS'sr case.

So, to make things a bit more understood, for those guys like myself that build up these "70 similar 400HP" cad 500s... If I rated my current near 500HP cad 500 engine in pre 71 specs, it would be close to 650HP....Now thats WAY overrated. The 70 eldorado is more like 295HP to the flywheel in todays ratings, so you can see that a bunch of HP is added on these built up 500s over what they really were....

All cars that are now legends are just really that in stock form, including Hemis, GTOs, Chevelles, corvettes, etc of the mid 60's early 70's.... In reality, what made those cars have the image that they were super fast, were the many guys that hot-rodded the crap out of them ... in many cases, some nearly doubled the actual HP of the original from mods, etc. Personally I was running a true 11 second 67 GTO on the street and it looked stock to a point.. I am sure that some youger guys today, remember my 67 flying and buying a restored one today from that image possibly not knowing that it is not that fast by todays standards. I was this way too, as I remember many 57 chevys that flew... In reality, a 57 chevy was a high 17 second car... My 360HP GTO was a 16 second 92MPH car when it was new and original. The images of those modded cars are the cars that todays high dollar buyers are reminicing over. Many of these guys were not a part of actually racing them back then and so many dont understand the fact that these resored "muscle" cars are by no means fast in todays standards....

One thing is for sure and no one can argue with this... Those cars are worth a fortune compared to a more expensive car like a cadillac of the same day. I would say that their overrated HP #'s, along with the 60's-70's modded cars that ruled the night time of america have everything to do with it... HP "ratings" sells cars.... Just explaining this to many it very tough as alot of todays "investment type" classic car buyers, have no clue that their wifes daily SLS will probably beat their classic 60's muscle car. They would say you are crazy for even thinking that... If they do really want to know, and I have done this on occasion, and get some to actually race their classic car agaisnt a car like an STS.. Once they are beaten a number of times, they are shocked and just dont understand the outcome. I say... "if you want to make that restored to orignal car fast".. I can tell you how.

Long live the old ratings! I really wish that all this nonscence would be dropped and rear wheel HP ratings were a standard along with a vehicles power to weight ratio... This takes the BS out of everything and tells the buyer what he is really getting."

[davesdeville]

Originally Posted by Ultra Slow

So, to make things a bit more understood, for those guys like myself that build up these "70 similar 400HP" cad 500s... If I rated my current near 500HP cad 500 engine in pre 71 specs, it would be close to 650HP....Now thats WAY overrated. The 70 eldorado is more like 295HP to the flywheel in todays ratings, so you can see that a bunch of HP is added on these built up 500s over what they really were....

You did get a bit carried away, but if one were to read that they would get a better understanding of the ratings.

Now you're trying to tell me a 70 500 at 10:1 compression will get less hp than a 76 500 at 8.5:1? I think you're not quite giving it the credit it deserves. I've heard from more than one source that a 76 gets 300-310hp and a link to one of the sources is in the original thread your post was put in. It only stands to reason that higher compression will give it a higher hp rating.

[Ralph]

I've read tons of musclecar mags in the 1980's when I was in HS. This was always a big topic. I researched my dad's 1971 Olds 442 W30, and it was rated at a conservative 360hp, (gross, before exhaust was attatched, fan belts, etc.) I read that in today's rating the actual is what a new DTS has, namely, the 442 is actually 300 hp! My dad always told me stories about the 442 having so much power (esp. on ice) that one time he took it to a hockey game, and at a stop sign it shook so much it almost went in the ditch! In other words, it had a lot of power! The fastest he had it up to was 150 mph with plenty of room to spare. So when I showed him his new DTS was actually the same power, he was suprised.

Something that always confused me is the rating of the street Hemi 426. Factory rated at 425, which seems low. Yet, I have read that it is actually 650 hp NET! Now, my question is, ratings were more then, so why was the hemi rated so low, and not overinflated like all other musclecars of the era? I understand about insurance rates, and the lower compression in 1971. Real musclecar enthuisiasts know that 1970 was the last truly great year for the ultimate in hp numbers.

[Ultra Slow]

There are no STOCK 76 500s that will do 300HP.... Thats like saying that my 80 cadillac is all stock and ran high 12's when it was new...... In fact the 76 big cadillacs were a good bit slower than the 77-81 cars for the obvious size difference..... Now on the 76, dump the cat, and you can start getting more power.. Put an intake, and full exhast and you will get close to the 300HP. Change the cam, raise the compression... No problem, the skys the limit to what you want to do. I will 100% agree that the 76 500 is a bit underrated at its 190HP, but it is not a 300HP engine in stock 100% original form. The reson that it is underrated is they used the Fuel Injection 500 for the ratings, thus really dropping the power.. The EFI motors through the late 70's and early 80's really were way slower than their carburated equivalant. Although the fuel injection is very cool, it is poor on performance as it was a first gen EFI system that a carb was simply superior to at the time in pretty much all aspects.

The Olds W30 was a great engine... Had 3 cars with high pump olds 455's in them. Was my favorite big engine for a long time and raced them all through the 80's. That is true that the W30 is about 300HP, but its more like 270-280 in reality if you used the 72-later ratings. It was fast for sure, but dont give the credit to the HP ratings as they were pretty much right on if measured in the 72 and later methods. What I did not go into big detail over in my original post was the torque. Motors like the W30, 70-500 cad, all had about 500ft lbs of torque to the flywheel.... Whatever crazy method car makers come up with rating HP, you cant jive the torque, and torque wins races on heavy street cars.. All street cars are heavy if they are over 2000LBS, according to the racing world.

Motors like the 70 Cad 500 are infact stronger motors than the Northstar, even though their HP ratings are lower than the Northstar on the same tests and ratings. They usually toted heavier cars than today. The torque on a 70 CAD-500 is WAY more than a N*, but the HP is a bit less... Torque is 200ft lbs over the N*.... Factor in torque with HP and you have a strong engine. A good designed and efficient running engine has about equal HP to torque, and the N* did just this and many modern engines do too! Not many big blocks do this... They usually have less HP than torque, and if you build them to have more HP than torque, they usually come apart pretty quick.

Take a motor thats ALL HP and little torque, you have a motor like they use in INDY... Yea its got 900HP in a 1200LB car, but put it in a 4000LB car and it will not run like you think it will, having to rev the crap out of it, and it wont last too long either. Same goes for putting a true 500HP built cadillac 500CID motor in a Simi Truck and comparing it the the avalible CAT-435HP Diesel that many high end rigs use. The cadillac 500 would barely pull that truck out the way compared to the Cat motor, and it would probably last about 2000 miles before it tore up under the stress and constand WOT use just to move the truck... Why..? Although the cadillac 500 has 500HP/600FT LBS... When that Cat-435HP is spooled up, its 435HP a bit less than the cadillac motor, but its creating more like 1200+ Ft Lbs of torque, and it does it at 1000 RPMS all day long without batting an eye. If that CAT-435 was not many thousand pounds itself, it would make a street car about as fast as you can get on the opposite extreme from an Indy engine.

With that said, take the N* and 70CAD 500 in the same car, the stock 70CAD motor is going to be faster, but dont think for one second its because it has more HP as it really does not... Its the torque.

An off the showroom, straight from the plant Hemis were not that strong stock. Like many other similar cars, they have created a legend due to the racing world of modified cars. Although I was never a mopar fan, still not either, and did not own a Hemi personally, I was around when these things were bought at the dealer and brought out to race againt like stock cars from GM. They were just a little stronger than a factory RAIV 69/70 Gto, and about the same as a 435 Corvette, and that was amazing in its day given the fact the cars hac very poor integrity, terrible suspension and just flat ugly... The Hemi cars were cheap compared to the vette, etc and ran about the same and that is what the fun of it was... A 426 Hemi Powered car was a mid/high 14 second car without mods off the showroom floor.... Add mods and they get fast as with all big CID, high compression motors of that time.

Comparing today, an STS is a 14:6 car, bone stock when driven right without the Mag drivers turning off the traction and locking out 1st gear.. Thus running high 15's as printed in many "weekly wipe" car publications.... It would give a STOCK hemi a darn good race down the 1/4 mile, and I dont have to tell you that it would kill the hemi past that.

With Hemi's as with most restored cars, . I dont think there are too many STOCK hemi engines around today even on the perfect restored original cars. Most get some upgrades to add power, and why not... In those days Hemi's and other muscle cars were quickly modified to have quite a bit more power than they rolled off the lot with, so again, the tales get taller with time as the people that actually raced them ALL modified them.

You have to remember that in the late 60's, dealerships were more than willing to add performance to new cars with things like headers, cams, intake, carbs, gears or whatever you wanted to the car... Many of the actual test cars that were given to mags like C&D, etc to print the test reports were not stock and had been massaged to be a good bit faster than the average one. This of course sells cars! The biggest thing I can tell anyone on a vehicles perfromace is "dont always believe what is printed" Many car manufactuers do get caught this way too.. The last one was late 90's 32V cobra... Claimed to be a low 13 car in the prints and hyped to the max. When actual motorheards bought these cobras and raced the crap out of them, pretty much evert one was a high 14 car stock, and the 32V motor is not easy to mod.. Ford bought back many of these, but this is a rare deal to see these manufatuers get caught.

There were many dealerships that built hot rod transplant cars in the 60's and I am sure most everyone knows them now.. Yenko, Baldwin, Berger, Nickey, etc... These were just chevy dealerships making a car the way many customers asked for in the past and created their own package of mods for them... All big profit! It was only when the strict EPA "PC" reign came about that they just blew it off and said they could not do it... Thanks to the EPA, these cars are worth increadible money today. Many of these cars were equivalant to 500-600HP cars in todays ratings, but were cars that were really no faster than a N* today before they were modified.

I am sure we will all be hearing about "how fast" the 86-90 5.0 mustangs were back in their day 30 years from now, as so many of them were hot rodded, blown up and trashed, creating an image of the car...... In reality, they are 15 second cars stock... In 30 years, 3 second 1/4 miles and 300MPH will probably be the standard in family car performance.

Originally Posted by Ralph

I've read tons of musclecar mags in the 1980's when I was in HS. This was always a big topic. I researched my dad's 1971 Olds 442 W30, and it was rated at a conservative 360hp, (gross, before exhaust was attatched, fan belts, etc.) I read that in today's rating the actual is what a new DTS has, namely, the 442 is actually 300 hp! My dad always told me stories about the 442 having so much power (esp. on ice) that one time he took it to a hockey game, and at a stop sign it shook so much it almost went in the ditch! In other words, it had a lot of power! The fastest he had it up to was 150 mph with plenty of room to spare. So when I showed him his new DTS was actually the same power, he was suprised.

Something that always confused me is the rating of the street Hemi 426. Factory rated at 425, which seems low. Yet, I have read that it is actually 650 hp NET! Now, my question is, ratings were more then, so why was the hemi rated so low, and not overinflated like all other musclecars of the era? I understand about insurance rates, and the lower compression in 1971. Real musclecar enthuisiasts know that 1970 was the last truly great year for the ultimate in hp numbers.

[92_Deville_on_20's]

Muscle cars in the 60/70's are classics, but definetly overrated as far as performance.

I find it hard to believe that those cars are faster than the cars these days STOCK from the factory. Muscle can't compare to the power, braking, handling, reliablity, and so on of new cars..period. Those cars are 30-40 years old and lack the technology.

Come on, we have cars from the factory laying down over 400hp to the flywheel stock and I can name so many cars that can run low 13's to mid 12's stock, and I not even talking exotics. I know several 4 bangers that will destroy any muscle you throw at it stock...example

Dodge Neon SRT-4..225hp 2.4L high 13's low 14's stock
Lancer EVO VIII...270hp 2.4L mid 13's in 1/4 mile
Subaru WRX STi...2.5L 300hp low 13's in 1/4 mile
Mustang Corba...5.4L V8 390hp mid 12's stock
ZO6..I don't even need to go there, we all should knew what she can do.

these are just a few examples, now here are some of my favorites..

BMW M5..the new one will sport a V10 and I sure it will have over 400hp
Mercedes SL 500 AMG..V8 493hp, need I say more..

[Ralph]

Originally Posted by 92_Deville_on_20's

Muscle cars in the 60/70's are classics, but definetly overrated as far as performance.

I find it hard to believe that those cars are faster than the cars these days STOCK from the factory. Muscle can't compare to the power, braking, handling, reliablity, and so on of new cars..period. Those cars are 30-40 years old and lack the technology.

Come on, we have cars from the factory laying down over 400hp to the flywheel stock and I can name so many cars that can run low 13's to mid 12's stock, and I not even talking exotics. I know several 4 bangers that will destroy any muscle you throw at it stock...example

Dodge Neon SRT-4..225hp 2.4L high 13's low 14's stock
Lancer EVO VIII...270hp 2.4L mid 13's in 1/4 mile
Subaru WRX STi...2.5L 300hp low 13's in 1/4 mile
Mustang Corba...5.4L V8 390hp mid 12's stock
ZO6..I don't even need to go there, we all should knew what she can do.

these are just a few examples, now here are some of my favorites..

BMW M5..the new one will sport a V10 and I sure it will have over 400hp
Mercedes SL 500 AMG..V8 493hp, need I say more..

I have the utmost respect for cars of the "original" muscle car era. 1964-1974. There would be no Cobra Mustangs, or SRT Neons if the original iron didn't exist. Considering that the old bias ply tires would smoke all day and lost traction badly in many a musclecar review, I would like to think that if I still had my dad's w30, with modern tires, I could kick-ass on any of the new whizz-bangers that they are making today. The cars of yesteryear (and they are plentyful today) didnot need technology to go fast, they had the torque, and the proper format to do it in, namely RWD. Put a set of modern performance radials on a nicely restored musclecar like the 1969 rt charger I has in HS, and I'll stun many a Civic ricer! I will never forget my buddy Neil in the mid-80's cruising with his black 1971 440 Charger. No hood, but the fattest slicks you could stuff in the rear. He would love terrorizing pediastrians on a Saturday night by literally raising the front wheels off the ground at a green light! Talk about torque! Lets see a WRX do that!!

[Ralph]

For Ultraslow, I remember the Cobra hp problem you are referring to in the late '90's. I believe it was the '98 or '99 Cobra, and Ford put the wrong camshaft in, so they had to recall hundreds of them. Ford was worried it would hurt their image, if I recall correctly.

[Ralph]

Also, I would like to add that I think you can have all the technology you can stuff into a car, but a well-trained or experienced driver can do things with a rear-wheel=old tech. that would match or near a trac. control or allwheel drive, etc. Manufacturers have admitted to adding tech more and more simply because not all drivers are good drivers, and things like anti-lock brakes, stabilitrac, traction control, heck even automatic door locks, because people forget things and do not care about the functioning of their automobile. Some people need to get back down to basics and understand aspects of their car and how it functions, handles, and the effects of variables on these.

My first car was a 1970 Plymouth, and it was a great car to learn on. I would not trade that experience for any other type of car, ie. allwheel drive, front wheel drive, more modern tech, etc. I am glad I learned how to handle a 4,000 pound car with rwd on sheer ice, or in a sideways skid or fishtail. 92 Deville on 20's., you mentioned that some of these cars are 30 to 40 years old, they still get the job done just fine. I have a 90 year old rifle that shoots as straight as anything new, what's your point?

You are right about many cars laying out 400 hp nowadays, and it was fun in the 1980's to watch the second wave of "musclecars" evolve and escalate from there. I believe it started with the 1982 GT Mustang, then Buick went turbo, then everyone else jumped on the bandwagon after that.

Mercedes SL 500 AMG, BMW M5, not too many people can probably afford one of those. You can get an older musclecar, work it, and get a lot more hp than that. Plus, things can be done to suspensions today that make any "old" car handle awsome. That is all.

[92_Deville_on_20's]

What are you smoking on. Muscle cars were nice in there day and when restored right they are still nice. One of my favorites is the 69 GTO Judge.

But, even with nice radial tires will NOT out perfrom a car like WRX STi or a ZO6 on the drag strip and DEFINETLY not on a road course or auto cross.

No low tech over weight tin can muscle car is going to out accelerrate, brake, or corner better than a nice sports car of today's era I.E...ZO6, WS6, SS Camaro, Mustang Cobra, WRX STi, EVO VIII, M3...Hell I don't think they can hang with some of the sedans or sport wagons they are putting out these days like a Mercedes E55 AMG or the Audi S4 wagon.

Have you ever watched the Gumball 3000 on DVD before. Basically it is a all out blitz a cross the county in some nices cars on the planet. They just straight punish the cars for 3000 miles doing 1** mph the whole way making it a challenge for any car. Yes alot of those cars are exotics, but some of them are also cars that most car afford that they take and mod. But, not of those cars are muscle cars...I wonder why.

Also, most of the cars I just mentioned are affordable by today's standard.

[lux hauler]

Originally Posted by 92_Deville_on_20's

Yes alot of those cars are exotics, but some of them are also cars that most car afford that they take and mod. But, not of those cars are muscle cars...I wonder why.

FWIW......there have been muscle cars that run the Gumball. I remember seeing pictures of a '72 Torino that competed as well as a 60's Mustang and a early 50's (?) Caddy.