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Why did Pontiac stop making the 389ci V8 motors so early? I thought Pontiac could've kept on making the 389ci V8 motors until 1970 and then change it to the 400 starting in 1971, to me the 389ci V8 is my favorite motor built in the Pontiacs and they deserved to last all the way through the end of the 1960s.
1971 was the magical year for auto manufacturers. That was the first big change in EPA and polution standards. If you can find charts you see things like,
I don't remember if those are exact figures but I do know that's the year they dropped everything back. The 389 couldn't make the grade to the new standards. But by going to the bigger engine, they could go by different standards. So they did.
1971 was the magical year for auto manufacturers. That was the first big change in EPA and polution standards. If you can find charts you see things like,
I don't remember if those are exact figures but I do know that's the year they dropped everything back. The 389 couldn't make the grade to the new standards. But by going to the bigger engine, they could go by different standards. So they did.
That was a major change in the horsepower increase/decrease between 1971 and 1972.
Didn't Ford/Mercury drop the 390 in favor of the 400 back in 1971 as well?
1971 was the magical year for auto manufacturers. That was the first big change in EPA and polution standards. If you can find charts you see things like,
I don't remember if those are exact figures but I do know that's the year they dropped everything back. The 389 couldn't make the grade to the new standards. But by going to the bigger engine, they could go by different standards. So they did.
What happened in 1972 to make them lose so much power? I find it hard to believe that a catalytic converter can cost almost 100hp.
What happened in 1972 to make them lose so much power? I find it hard to believe that a catalytic converter can cost almost 100hp.
(Did they even have cats in'72?)
Because the 1971 figure is gross hp and the 1972 figure is net.
They really didn't lose that much, it just seems so when comparing gross with net.
For instance, the 1971 rating for the 472 Cadillac engine was 345 hp gross and 235 hp net. The same exact engine, just two different ratings.
And catalytic converters didn't appear until 1975. The 1972 cars didn't have them yet.
Because the 1971 figure is gross hp and the 1972 figure is net.
They really didn't lose that much, it just seems so when comparing gross with net.
For instance, the 1971 rating for the 472 Cadillac engine was 345 hp gross and 235 hp net. The same exact engine, just two different ratings.
And catalytic converters didn't appear until 1975. The 1972 cars didn't have them yet.
I didn't like how they have changed the horsepower ratings from gross to net, is net the real rating of the horsepower or is it gross?
Also why did the catalytic converters have to arrive on them cars back in 1975.
Wasn't the 1973 Pontiac Trans Am SD 455 the final car until the 1990s to have at least 300 horses?
I didn't like how they have changed the horsepower ratings from gross to net, is net the real rating of the horsepower or is it gross?
I like gross better, too. "375" hp sounds better than "280" hp.
Gross is the rating with no accessories (alternator, water pump, full exhaust system, etc.) Net is with full accessories and is more realistic. It could be said that the gross hp is what an engine makes under ideal conditions and with no accessories to rob hp.
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Also why did the catalytic converters have to arrive on them cars back in 1975.
Because the emissions were getting more strict and items like air pumps and EGR valves were not enough to meet the emissions.
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Wasn't the 1973 Pontiac Trans Am SD 455 the final car until the 1990s to have at least 300 horses?
I would have to look it up, but it most likely was the last with 300 net hp.
If I recall correctly, the 389 was replaced in 1967 with the 400 Pontiac.
Not sure why they killed it, I guess Pontiac figured back then "the bigger the better". Even though up until 1970 GM had a rule of "no more than 400 cubes in passenger autombiles. Corvettes excluded".
I'm sure during the 1st and maybe even the 2nd gas crunch people cringed at how was their 3 deuce 389 gonna survive. I'm sure anyone who drove one made regular use of the 3 carbs.
Fleet is correct, no cats until 1975, automakers began rating the engines fully loaded in 1972 as opposed to just the engine no accessories (like they had been doing) on the dyno.
I believe automakers started doing this in an attempt to make their cars appeal more since now the insurance company was anal raping anyone that wanted a muscle car. Which I'm sure made some think twice until the automakers convinced the insurance companies that their cars weren't really making the power they were.
I think the 1973 455 SD Trans AM was the last car until the 90's rated at over 300 hp, though there were a few that did come close.
I think the 1973 455 SD Trans AM was the last car until the 90's rated at over 300 hp, though there were a few that did come close.
My 1987 Trans Am only came with 225 hp, and that was the biggest available engine(350). It can't hang with the newer ones, but oh well, it's plenty enough for me.
My 1987 Trans Am only came with 225 hp, and that was the biggest available engine(350). It can't hang with the newer ones, but oh well, it's plenty enough for me.
1987 Buick GNX's with their single turbo V6, were rated at 276 hp and 360 tq and could give a 1987 Corvette a run for it's money. Two years later they put the same turbo V6 in the 1989 Trans AM for the Indianapolis 500 pace car. I think it even still holds the record for the fastest factory built US production Trans AM.
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? I find it hard to believe that a catalytic converter can cost almost 100hp.
