how come when you look at some of the older engines from say the 60's, you got engines like 283's making 250 hp, and 327's and 350's easily making over 300 hp in alot of the cars, then you go to the 80's and you got 350's down in the 170 and 190 hp range, is this because of some emmisions thing that were all of a sudden put in the engines? is it better to rebuild or use a engine from say the early 70's instead of one from some pickup from the 80's? btw i'm talking about carburated engines in the 80's, not the fuel injected ones..

 

they had so much power as back in the day the only emmisons would be (for my 68) "set timing at 8 degrees and idle speed at 750 RPM" also back then emmisons were unheard of, gas was 108 leaded and they could run the deep breathing heads, big cams duel exhaust, no cats, 10.5:1 or higher compression and other performance goodies right off the factory showroom, once emmisons took it's first swing in 73' making the power go into the crapper, then the nail in the coffin in 80' when big cube engines were unherd of, 400's and 455's in the firebirds and 350's in the camaro were now just a dream of the past. only power engines were the mediocre at best 301 for the firebird and the 305 for the camaro. GM didnt know how to get the emmisions down so they just kept dropping the compression, putting in smogged out to hell heads and intakes, TINY cams and cats were starting to be used (VERY restrictive) that lasted untill finally with the LS-6 cars GM has found a way to make power while still keeping it emmisons happy, the low power and small cubes in a nutshell was just from emmisions. also the engines main things like the blocks were allways the same quilty mostly, the early 70's late 60's were the stongest having the most nickel content, but all were fine, its reall the later engines have horrible smogged out heads, intakes and dished pistons.

[This message has been edited by TempesT68 (edited November 21, 2001).]

 

hey thanks alot for that reply, i guess if i want to get my car with the mad horsepower of those late 60's cars, i gotta invest a little money :-)

 

The engines were not that much stronger. The
Horsepower was calulated differently.
Gross HP in the 60&70'a
Net HP in the 80's to the present.
I will let you figure it out.

[This message has been edited by Z28DJP1987 (edited November 21, 2001).]

 

gross and net hey, i figuring that one means average and one means total? i dont know, i think that TempesT68 was pretty accurate when he said that there were no emmision laws back then, so they could do whatever they wanted, and run them on 107 gas..
i'll just try and pick up an early 70's 350 and hope that it has some nice strong good parts in her :-) cause they 350 carb engines are puting out like 170 HP in alot of cases, get that same **** from a 305 thats in my car right now..

 

they started to use gross in 1970 i belive, but still just the gross was just a bit under the net readings anyhow, dont forget this was back in the days of leaded fuel, powerhouse engines and factory 12 second cars, NOTHING like that came out in the 80's, the 80's was the worst tooling used on any time from the 50s to present if you really look at it,..........well except for the GN, that was one BAAAAD SOB

 

I see everyone still think the diffence in
Horsepower on the 60&70 cars was the absents
of emmission contols. Another question? 1967
427 corvette with Gross HP rating or a 2001
350 corvette with Net HP rating which is faster and has the most HP???

 

right like i posted the LS-1 is the only engine to come out in a LONG time that can make very impressive power and still be emmisions happy, the automakers are now finding out to work with emmisons, but makes the hottrodder unhappy, every look under the hood of a ls1? would take you 8 weeks to put in headers and probley 3 years to get the engine out

 

Gross HP is about 25% higher than Net HP. It was in either 71 or 72 that they went to Net HP.

But that isn't the whole picture either when it comes to HP ratings. I would say the small blocks were close to their proper Gross ratings in the late 60s/early 70s. But big blocks were a whole different story. Due to insurance (and other factors), most big blocks were underrated. So their actual NET HP was probably significant higher than their advertised GROSS rating.

A good example is the BBC L88 427 (rated 430 HP, but well over 500 HP) and the 426 Hemi (rated 425 HP but closer to 550 HP). There were a lot of games played when it came to HP ratings.

 

that is correct most of the rating were much lower on there performance engines, like on the 70' buick gs 455 had a rating of 350 HP and 510 Ft. lbs. of torque, but the stage 1 engine was rated only 10 HP more and 5 more ft. lbs. but was really dynoed at about 425 HP and 575 ft lbs. it was running high 12's all day with a auto, a/c and all the power options in that tank of a buick weighting about 4,200 lbs. pretty damn impressive if i do say so ahhh the old day, 3,500$ you could order a brand new right off the showroom floor a monster cubed big block car with over 400 HP running 12's,...............

[This message has been edited by TempesT68 (edited November 23, 2001).]

 

When you buy a brand new car, the tax that you pay comes from the horsepower rating. My '82 T/A is suposed to have 145 hp. But it keeps up with a '92 RS that was suposed to have 190 hp. That's also why GM always underates their engines. Just another reason.

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...
http://www.spinfrenzy.com/stingerssx...easures.html#4

 

I side with the gas and emmisions. Some of those old big blocks ran 13:1 compression.

the key to making power is in the HEADS and CAM of an engine........not what year it was made. The best technology in this category comes from today, use new speed parts and be faster is the lesson.

[This message has been edited by vortecfcar (edited December 01, 2001).]

 

How about some actual information?

Up through 1972, engines were rated using gross HP - meaning the engines were run on a dyno with no accessories being turned by the engine (including water pump), no air cleaner on the carb, and either open exhaust or even headers. They didn't even have to be tuned to the specs under which the engines were delivered in the cars.

After that, net HP rating was required - normal accessories installed and turned by the engine (water pump and alternator typically); all as-installed components such as air cleaner, exhaust; and tuned as delivered. Emissions had some effect also, especially with lowered compression ratios and detuning that started in 1972, but having to run the engine with its accessories had the most effect. That is also why the same engine in '86 year model LG4's, for instance, could have differently rated HP because of exhaust differences even though internally they are exactly the same.

For an example of the earlier practices, my '66 396 with 10.25:1 compression, 750 CFM q-jet, rated at 325 HP, came from the factory with an air cleaner snorkel opening that was somewhere between the size of a quarter and half dollar. Do you honestly believe it would pull 325 horse with that air cleaner installed?

Me neither.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

five7kid
I agree, horsepower was overstated in those
years on PRODUCTION cars sold to th public.
They were not the best and I owned a few when they were new.
62 327 ss chevy
63 327 corvette
66 396 ss chevy
69 400 Gran Prix

 

Its nice to know that even stock you've got more power then they claim, not the other way around like that 1 ford car, what was it?!