1. Yes and No. Horsepower on the 350 was down 55 horses at worse directly related to emissions requirements (155 vice 210). However, the Z28 (and it's engine) died because of poor sales. The LS6 454 died because no one bought them due to the cost of insurence.

Another intresting point, Chrysler's top 4 barrel 440 engine in 1972 (carry over from '71 save the net rating) put out 245hp & 360 torque. In '73, it went up to 275 & 380. Ditto 1974. But the Challenger and Barracuda didn't even make it through '74. Point is manufacturers aren't going to put their money where it's not going to do them any good. In '75 Chrysler ripped the 440s out of everything save trucks and some large cars because people weren't buying big engine cars anymore. Horsepower dropped a mere 25 to 250.

2. There was no high performance 350 in 1980. Only the LM1. Only difference was it had solenoid flaps in the hood that brought in air at WOT. The LT1 had performance parts (different head, cam, intakes), and can't be compared to anything. However, the baseline 350 4 barrel was a constant from 1967 up to 1981. Not talking about marketing, I'm talking about emissions actual affect on horsepower. The 350 4 barrel is a perfect yardstick.

2. We aren't talking about Europe. The issue is how much did emissions standards reallystarve horsepower over here.

3. Oldsmobile's 455:
365 (gross hp) in 1970.
340 gross in '71 (which calls their 1970 rating into suspicion since it was the same engine)
270 net in 1972 (same engine different way of rating)
250 in '73 & '74

Production ended in 1976.

When GM stopped using dual exhausts, and used a single converter instead of twins, the final 455s were rated at 210 horsepower, about a 40 horse drop (about 60 from the emissions free days of '72 and prior).

Safe to say Olds' engines with duals had under 300 without emissions and 250 with. This corresponds with our 350 4 barrel Chevrolet's losses due to emissions equptment.

BTW: GM used single exhausts due to cost savings, not emissions regulations.

Some Chrysler V8s used duals well into the 1980s. Even the Mustang II 2.6 V6 had duals feeding into a large rear muffler with twin outlets.

 

Actually, the 1971 Chrysler 440 had 305 net hp as installed in the Charger and its brethren.

If you're trying to compare emission effects on horsepower as in your second #2, you should be taking into account internal engine changes as in your first #2. The 1971 LT1 could never have passed 1980 emission standards. So to just compare an engine that does pass them with a derestricted version of itself understates the loss of horsepower.

Secondly, the difference between a European-legal engine and American-legal engine is a perfect indicator of how much emission standards cost in terms of horsepower lost over here. The chemistry and physics are the same, no matter who builds it.

You've got a number of things wrong above. In 1970, it was 365 gross for the standard 455 with 4bbl carb. In 1971, it was 340, but that was due to the change in compression. The net in 1971 varied substantially depending on single or dual exhaust and 442 versus B-bodies. The W30 model was rated at 300 net in 1971.

By 1975 with the cat, it was 190, not 210. The 403 that replaced it in 1977 had 185hp, a minimal loss.

Dual exhaust was available with the 455 until 1975. The extra cost up until catcons was minimal. After catcons, the exhaust systems became much more expensive. It wasn't until many years later that GM even engineered a system with dual cats. So I'd say the loss of dual exhaust was directly related to emission standards, because those standards made it too expensive to offer.

So lets recount. The 1970 Olds W30 engine made a supposed 370 gross hp. Net was around 320, based on acceleration times recorded in that era. The lower compression engine (lower compression because of emission standards) had 300. By 1976, the single exhaust standard engine (W30 engine wouldn't pass emission standards, dual exhaust was too expensive to engineer and produce for anticipated volume, because of emission standards) was 190hp.

I guess you can restrict your field of inquiry as much as you want, ignoring second order effects -- such as emission standards making dual exhaust much more expensive, former high performance engines unable to pass emission standards leaving only standard models, emission standards forcing lower compression engines -- and maybe come to a conclusion that the effect on power was minimal. However, I think you end up with the wrong conclusion.

If the U.S. had had European standards, I think it highly likely that there would have been some sort of 1980 Z28 with more like 275 hp, which though still not equal to the musclecars of yore, at least could still be called at least a 1/2 muscle car in the way that the actual 190hp model could not. So that gets me back to where I said I 1/2 agree.

 

A quick little thought experiment.

Let's say the new Camaro comes out in 2009 with 400hp. Then it gets 430 in 2010. In 2011, due to new SULEV emission standards, it drops to 360. It says there for a few years, then in 2015, it drops to 300 because it runs on hydrogen.

GM determines that they could develop a high performance option with 340hp, but with anticipated volume, it would be a $4000 option.

How many people would want to spend that money versus just go out and buy a 2010 model? Btw, the 2010 models are really cheap, because they still run on gasoline, and gasoline is being taxed heavily to convince people to buy hydrogen and save the air.