I take issue with you guys who think GM knowingly made defective gaskets. I think they were a bad design and it took a while for that to show up. Not every car out of the millions of 3.8's have had the gaskets go bad. Mine didn't until 308,000 miles. Now tell me how back in the day cars even lasted that long. Go ahead and brag about how you had to change plugs every 25,000 to 50,000 miles and distributor woes and how they got 15 miles to the gallon. On the other hand, they did have class and style and good names like Bonneville, Star Chief, GTO, Lemans, Catalina and Grand Prix; not original names like G3, G5, G6, G8.
For longevity, I'll take a modern 3.8 anyday over anything before them. But for sound and power, I'll take the old 389s and 400s.
Most people don't keep a car until it gives up the ghost. They get the hots for a newer sleeker hotter looking model. Getting a bad reputation for making junk won't get you new sales. So I don't think they ever purposely made defective parts. I'm not sure they reacted quickly enough once they realized what happened with the gaskets.
All that said, I'm sure the engineers at GM are a lot smarter than me, but at least I haven't gone bankrupt yet. All that may change when I retire next month.