What are the real hp numbers?

Sadistic

Sadistic

Der Bismarck
Joined
Mar 25, 2008
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Palm Bay, Florida
For example, 427/435 hp is gross rating. Have any of these cars been dynoed stock to see how they compare to newer net ratings? Is 435hp really only about 350hp by today's standards?
 
I am not disappointed. My engine is far from stock anyway. I will dyno it at some point to see what it actually has. My question is not really related to my car. I was just curious as to what kind of numbers they actually put down in stock form, compared to the new vettes. I know that a ZL1, with open headers did the 1/4 mile with 130mph trap speeds. However, most of the big power big blocks from the day were so limited by tires that they didn't even see 120mph in the 1/4.
 
hehehe....rather interesting topic, from back when Dodge/Plymouth tossed a set of headers into a street hemi trunk, and shipped it.....

the ONLY thing one needed do was change the cam, complete with MOPAR part #, and that muvva made nothing but smoke outta anything on the diffy....I mean stand there down the track a ways, see other cars come outta the hole much quicker, but then that damn hemi got wound up, and RUN their asses down like no tomorrow,....like a Leopard on a hunt....

then there was the odd ball vettes.....with all sorts of engine combos of which NCRS has documented about 3x the legit stock production numbers....so go figger what in hell THAT means.....

as for the aluminum headed 427s' I heard all sorts of stories, but 550 hp sticks to mind somehow....pretty close anyway....supposedly...

but as we all know, that was wide open exhaust on the engine dyno with no accessories not sure about aircleaners even required....so guess it depended on who ran the tests, and that depends.....

early 70's before the feds demanded legit in car ratings at the crank....and all the BS numbers fell like a rock....

crap, wasn't untill mid 80's that anything decent in performance came back on the scene 15 years of desert.....

I had a Dodge Shadow ES turbo quick little skunk, had a turbo colt too, the original pocket rocket from '84 crank that puppy up a bit and....snicker....

only two boosted cars I ever owned....
 
The only thing I ever really heard was that Edelbrock put a crate L-88 on their dyno, right out of the box, added a set of good headers and it made 550+ without any tuning. That one GM said was 427/430.
 
TimAT said:
The only thing I ever really heard was that Edelbrock put a crate L-88 on their dyno, right out of the box, added a set of good headers and it made 550+ without any tuning. That one GM said was 427/430.
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THAT is why I say i'ts such a complicated issue, SO many decades have past, and lord knows gasolines with various polycantpronounceits in there then the verifyable repeatable results which engineering types rely on for making product/design decisions.....

in other words, can GM/Ford/Chrysler build a NASCAR engine and sell it in a street machine??? well theoretically they probably could, cost effective?? hell NO, POSSIBLE, yes....

now the crux of the matter, would it run say 200K miles without blowup in EACH OF some 50,000 cars.....


:gurney::gurney::gurney::gurney::gurney:
 
TimAT said:
The only thing I ever really heard was that Edelbrock put a crate L-88 on their dyno, right out of the box, added a set of good headers and it made 550+ without any tuning. That one GM said was 427/430.
Click to expand...


There are some ZL1 dyno sheets floating around--if I remember correctly they were around 540 hp.:smash:
 
ONE thing noted, for all the ballyhoo and bullshit, so it seems that 1 hp/cu inch displacement is a goodly bench mark of a decent engine....

and rare to find one actually doing that even today....

:stirpot:
 
I find it interesting/amusing how easy it was for GM to "alter" HP numbers. For example...when the L-72 427 first came out it was rated at 450HP. That was thought to be pretty accurate for those days. But the insurance companies screamed bloody murder. So GM just changed the decal on the air cleaner to 425 HP. Presto....the insurance companies were happy. No change was made to the engine AT ALL. Both the L-88 and ZL-1 were very under-rated for HP. The 302 Z-28 engine was WAY under-rated at 290HP. A more accurate number was thought to be anywhere from 350-365HP or MORE, depending on induction system.
 
DJ Dep said:
I find it interesting/amusing how easy it was for GM to "alter" HP numbers. For example...when the L-72 427 first came out it was rated at 450HP. That was thought to be pretty accurate for those days. But the insurance companies screamed bloody murder. So GM just changed the decal on the air cleaner to 425 HP. Presto....the insurance companies were happy. No change was made to the engine AT ALL. Both the L-88 and ZL-1 were very under-rated for HP. The 302 Z-28 engine was WAY under-rated at 290HP. A more accurate number was thought to be anywhere from 350-365HP or MORE, depending on induction system.
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I forget why, but HP is typically measured at 5250 so it varies from idle to there or whereever they want to measure it at.....so somewhere in there it made 425 hp.....woopie doo.....

stick a cam in it and it does 550 hp....woopie doo....

stick a can of nitrous on it, and hold onto your HAT......

stick it on a Boss Hoss frame, and hold on to your BALLS.....


:1st::shocking::beer:
 
5250 is the rpm where the TQ and HP curve cross IF both are plotted out @ the same scale. This 5250 only applies to IMPERIAL values, if you use a different nomenclature it does not fly. The 5250 is simply a result of chosen constants and simple mechanics laws.
 
Twin_Turbo said:
5250 is the rpm where the TQ and HP curve cross IF both are plotted out @ the same scale. This 5250 only applies to IMPERIAL values, if you use a different nomenclature it does not fly. The 5250 is simply a result of chosen constants and simple mechanics laws.
Click to expand...

I know that, so is why I used the term 'typically'....:D
 
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