Challenger 340 power output

[Mark_B]

Hi All,

I have often wondered why Dodge advertised the base model 1970 Challenger 340 with 275bhp, yet for 1971 the 340 R/T had a reduced engine compression ratio, but still gave the 275 bhp figures.  Surely there would have been a drop in bhp?


1970 Challenger - 340  Compression ratio - 10.5:1 - 275 BHP

1971 Challenger R/T - 340  Compression ratio - 10.3:1 - 275 BHP


Any thoughts welcome.

[ec_co]

In 1971, the major change in horsepower ratings was the shift from "gross horsepower" to "net horsepower," meaning that manufacturers began reporting engine power with accessories like air cleaners and exhaust systems attached, resulting in significantly lower horsepower numbers compared to the previously reported gross figures, which were measured without these components on the engine alone; this change was primarily due to stricter emissions regulations and the need to use lower compression engines to accommodate unleaded fuel.

So in other words, a change in government regulations for how manufacturers measure the horsepower.

[Mark_B]

The figures I gave above are both gross horse power. 

[RUNCHARGER]

More CFM in 71 with the TQ, they were actually a bit stronger than the 70. The ratings were a bit low for both of them, just take on a 290HP, 2 bbl 383 and you'll see.

[BZaar]

For those of us old enough to remember the early 70s there were a lot of "fictional" HP numbers published to keep insurance rates lower and sell more cars here in the US.  I distinctly remember thinking as a young man that I might be able to afford the payment on a new Mopar, but the insurance would be more than the monthly payment ! There was a big difference between published HP and actual HP.

[Mark_B]

More CFM in 71 with the TQ, they were actually a bit stronger than the 70. The ratings were a bit low for both of them, just take on a 290HP, 2 bbl 383 and you'll see.

Thanks for the information.  That will explain it. Learn something new every day!

The 340 is lighter than a 383 too, which would help performance.

[tparker]

What, car companies not being accurate with numbers? LOL. What car get's advertised MPGs or who pays anything close to that sticker price. 

I have always heard it was for insurance reasons. A lot of the articles I've read say that, but not sure if that is true. It kinda makes sense if your targeting the youth market. I also wonder if it had anything to do with the emissions laws that were coming out. I wonder if HP had anything to do with the regulations that were coming out at the time. Good question.

Tom