I'm aware that the '72 Cutlass U Code engine's horsepower was rated 455/250 NET. What was the '71 442 Automatic horsepower? Was the '71 rated the same way, net? If not, does anyone know the objective horsepower assuming both engines were rated identically? Also, was there a performance difference assuming both cars were convertibles, optioned identically, and both cars were equipped with automatic transmissions?

 

In '71, they showed both gross & net h.p. in the Specifications for engines. The 442 is listed as 340 gross, 270 net. It does not give separate listings by transmissions. The L31 and L32 are listed as 320 gross, 250 net, but no trans mentioned. These last two would have been for the other applications other than the 442, the 88,98, SX. I always thought that the '71 and '72 engines were the same. You would probably have to look at the engine assy. manuals to see if cams etc. are the same.

 

What changed in '72 to drop the net horsepower?

 

It looks like the cam changed. Do you have a copy of 442 By The Numbers? it lists the camshafts, I was unable to upload a scan from my computer.

 

Why?

 

The 71 and 72 engines are the same. The U code puts out 250 net. The V code puts out 270 net. The X code is....300 I think?

 

The '71 442 auto trans uses a different cam than the '72 auto.

 

 

'71 auto uses 400165, '72 auto uses 409691. Overlap seems to be the biggest difference.

 

Ok, there's the difference then. People think the pistons got changed or something for the apparent drop in HP.

 

Is the difference in cams significant enough to account for the difference in rated horsepower?

 

It's not much. I think taking a good dump can net you the same benefits by weight loss. So, maybe?

 

The problem is that you are believing the published HP numbers. In prior years, Olds made a point of noting the lower HP in the 442 AT motors (325 HP vs 350 HP in the 1968-69 cars, for example). They did not do that in the 1971 specs. The 270 HP/370 ft-lbs (net) shown for the 1971 442 is exactly the same as the 270 HP/370 ft-lbs shown for the 1972 MT motor. Wanna bet that the 1971 AT motor made the same 250 HP/370 ft-lbs as the 1972 AT motor?

And don't get me started on the 1970 W30 motors...

 

So your point is that the horsepower ratings are not accurately representative from the factory...and ....​​​​​the '71 and '72 automatic transmission engines are the same engines, and horsepower, irrespective of the ratings?

 

The differences between the 71 and 72 cams is in the noise. As for the accuracy of the factory ratings, do you really believe that the 285/287 cam in the W30 AT motor made the same HP and torque as the 328/328 cam in the MT motor? Or that either of them made LESS HP and torque than the Toro W34 motor (with the same 285/287 cam, E heads, and the crappy Toro intake and exhaust manifolds)? And if that's true, why did Olds waste all that money on the unique W30 parts to make LESS HP and torque?

 

The '71 and '72 automatic transmission, non W-30 engines, generated the same horsepower?