Hello everyone. This is my first post here.

I was just browsing through a short history of the F-Series and read that the inline-6 made its debut in 1965 and the 300 cid version cranked out 170 hp. Then I read that the exact same engine only had a 114 hp rating in 1978.

Question: Did the hp drop suddenly in '78 or did the change start earlier and gradually?

Thanks in advance.

 

Auto companies changed the way they measured horsepower in 1972, and that reduced the published horsepower. 78 was also an emissions engine.

 

manufacturers used to state horsepower from the engine, now it's to the rear wheels.

 

Wrong. No manufactures state rear wheel horsepower. Before 72 they tested motors with no accessories or exhaust, now they test to SAE standard, but it is still flywheel horsepower.

 

According to Ford archives "in 1981 122hp at 3000 rpm and 255 ft. lbs torque at 1400 rpm

 

stteell

Thanks for the correction. I was totally mislead over the years. I looked up my corvette history "a switch from SAE gross to SAE net power ratings" I always thought this meant gross at engine, net at rear wheel. Geez, no accessories or exhaust, glad they changed, that's a little misleading.

 

how much power is lost by the time it gets to the wheels. anybody know what the horsepower is for the 04 F150 to the wheels?

 

I used to have a '46 Plymouth with a flathead six. It still had the owner's manual. It said the engine was rated at 90 HP as I recall. Then it said "usable horsepower" which was at the road. It was only something like 12 or 17 HP. I forget exactly but I know it was just a fraction of the rating that was usually advertised. I imagine the difference is still pretty wide even with today's ratings.

It's no wonder Detroit quit using numbers like that a long time ago and still doesn't. It would be interesting though if they did, a little reality never hurt anyone. It sure would change the way a lot of people think.

 

I think 15 - 20% drivetrain loss is generally accepted.

 

Your plymouth used what they call in Europe as taxable horsepower which is rated real low