What are the pontential hp ratings for the 426 hemi?

Question

The 426 hemi was rated from the factory with 425 hp. I have read elsewhere that it was slighty underrated Actually has 430hp. I have also read that it was very underrated And may have had 600hp, I have even seen claims have as high as 800hp. Then again one 2 engines are the same And they did not have the manufacturing technology we do today so all engines were hand built. What do you think?

Answer 1

The 426 was rated 425 horse power at the crank. But was under rated to keep the insurance companies happy. The horse power ratings were closer to 500. But compare hp and torque ratings to figure the best bite. Hp without torque is just another boat anchor. Factor in(at what) RPM, the right combination, and power to weight ratio will get you there in a hurry.

Answer 2

When the second generation Hemi engine was undergoing development there were many that dynoed in excess of 500 horsepower in what was expected to be "stock" form if the engine was released to the general public but that did not happen. Development continued on the engine as a race engine only and horsepower figures on the factory dynos climbed, but when the Hemi dominated NASCAR in 1964 NASCAR caved to GM and Ford's complaints and ruled "all" engines raced had to be made available to the general public, thereby the general public Hemi was created and rated at 425 gross horsepower with two four barrel Carter carbs and GM's "mystery 427" disappeared from the NASCAR ovals but did enjoy some success at 1/4 mile venues.



The engine was built for "brute"horsepower and nothing more, it was not fuel efficient, burned about a quart of oil between oil changes due to engine clearances, had solid lifters that needed adjusting every couple of months and needed the carbs adjusted occasionally.



Chrysler tamed the engine with hydraulic lifters about 1968 I believe and made some tuning improvements which helped on the street without taking away the "brutishness" of the engine but it was still a "heavy drinker" at the fuel pump. Shortly after, the writing was on the wall as insurance rates and emissions standards increased and it became obvious big block high horsepower engines were doomed.



Engines today are more efficient and produce high horsepower numbers but the more power you pull from an engine the shorter it's life span and there is nothing you can do to increase horsepower on these engines unless it's a turbo, NOX or a new ECM. "Back in the day", I saw big block engines in cars go in excess of 250,000 miles with no work other than oil changes and tune-ups. Want another 125 horsepower, a new four barrel, intake, cam, headers, a little port matching, advance the timing a few degrees, a touch or two on distributor springs, a 2 1/2 inch ID exhaust and you're there.



Cars today are fine machines regardless of manufacturer but to put your foot on the floor and burn two divots in the asphalt with the rear tires . . . . .

Answer 3

The 426 never produced 425 SAE net horsepower. It produced 425 gross horsepower, which translates to 350 SAE net horsepower which is what all vehicles are rated in today.



http://en.wikipedia.org/wiki/Chrysler_Hemi_engine#426:_The_Elephant



So actually, it was overrated. Maybe it was better than the emissions clogged and unleaded engines of the early 80s, but it doesn't hold a candle against many modern engines.



It could produce those powers, but it would have to have the internals done, be blown, and run on alcohol most likely.



Also, the Hemi is a completely obsolete concept. You get more power from swirl and proper mixing rather than direct cross flow. This is why modern Dodge Hemis are only Hemi enough to use the name... they aren't really Hemis at all...

Answer 4

600 HPs stock? no way buddy, not even close, really, the potential HPs its practically endless, I bet you first run out of money, I mean you can change or improve EVERY SINGLE PART, even the engine block itself to reach your desired power.



Look, you can use a car performance simulator to virtually tune that engine, any mod you may like and see how a car improves with the new upgrades, try at http://www.nxgtrsim.com