440 stock specs

[q-ship]

In 1967 they advertise there 440 at 375 horspower. Is that an accurate number?

As accurate as the testing methods that the factories choose to use back then, but about twice what the current power rating standard is.

Ratings were BHP till 1971, then SAE net after that (which were still fairly arbitrary, but tightening every year), then in 2005 everyone had to go to SAE net "certified" ratings.

So a 67 "production" 440 probably had closer to 280 (SAE certified HP). -- "my estimate". Due to the 375 HP ratings being based on a hand built, perfect, test engine running no accessory drives, no water pump or fan, no air cleaner, etc. VS. production engines of today, with all accessories - full exhaust - mufflers, etc, installed for testing.

This is one of the reasons that the older engines respond so well to otherwise small improvements, whereas the new era engines won't gain near as much for a similar change.

As a correction to other posts, NASCAR never had a HP limit, but has always had a 430 cubic inch limit.

Underrating HP was for the export market, as HP had sever tax implications for exports. U.S. insurance was always based on the model, not the HP rating (how stupid does anyone think the insurance industry was/is)???

Aside note, the 426 Hemi, which was capable of extreme HP, was severely limited by it's need to meet production (street) car functionality. A Hemi could be made to produce massive power, but the production version could rarely beat a 440 on the street or strip, as it was severely de-tuned, to be functional as a passenger car engine. 425 HP was probably generous for the time and how it was built "especially by todays standards".

In production form, it's torque sucked, and just as it was coming into it's element at higher RPM, the cam fell off. This is not a knock on the Hemi, as it was a race engine, that had to be installed in a certain amount of "street" cars in order to be race legal in NASCAR and SS racing.

In any event, even wondering about HP in a street engine (or how it's rated) is silly, since torque is king in anything other than a full tilt race car, and the wedge engines were built for world beating torque, at the expense of HP.

The modern engines are quicker, but they have decades of technology to help them, such as 3.5 ratio (or lower) first gears. more gears, better head design, EFI and computer controlled timing, etc; to help them. But the old wedge can hold it's own if built with current technology, but "67" stock, will get left in the dust.

As a final point, when was the last time you saw a magazine dyno an engine at a "SAE net - certified" rating? NEVER, after all they have to sell magazines.

 

[696pack]

The Hemi engine was hand built, correct? And I'm sure they took more time to make sure it was right but regular production engines were all over the board with the horsepower number and tolerances but if you want to believe the hp numbers were correct and on the money, that's fine with me. There was also no core shift in any of the castings what so ever and all bodies had no fitment issues either.....

ALL factory engines back then were "hand built" there were no robots in the assembly process back then.

Not arguing that there were production differences. It is well known that Mopar engines are typically down in the hole compression wise. There could be VAST differences with the same engines. There was a local hometown 1968 383 RR Auto 3.23 car back in 1968 that was stone stock that regularly out ran 440 cars in the 1/4 on the street. There were cars that the engines were simply "accidently" built just right, had the true advertised compression, and were somewhat factory "blueprinted" with better torerances that most of the factory engines that left the factory. The car I am speaking of above was likely one of those cars.

What I have been speaking of in this thread is what the factory randomly tested engines ran out as h.p. wise when testing for the advertised h.p. rating. As said, they were rated at low rpms and the engines peaked at higher rpms. it was a insurance and amufacturer's competion game and they rated them where they wanted them for these reasons.