If we ever get around to doing an Ultimate Engine Survivors list (to accompany the Survivor Cars list), this engine will surely be near the top. 47 years and counting!
If you like weird twists and turns in your engine-history plot, you'll like the Buick V6. Buick engineers took their aluminum 215-cube V8, lopped off a couple of cylinders, and cast the shortened block and heads in cast iron. The result displaced 198 cubes and made its debut (as the "Fireball V6") in the 1962 Buick Special. Oldsmobile and Buick dropped the 198 and later 225 into their A-bodies, but The General made the decision to use the Chevrolet I6 250 as their six-banger of choice. The V6 was sold off to… ready for this? Kaiser-Jeep! When those Kenosha swashbucklers at AMC bought Kaiser-Jeep in 1970, the bulletproof AMC Straight Six shoved the Buick aside.
Fast-forward to the dawn of the Malaise Era: "Rat turds!" screamed The General's suits up on the Fourteenth Floor, "We need a V6, like, yesterday! So, all the Buick V6 tooling traveled back from Wisconsin to Detroit and the world was introduced to the 231-cubic-inch "new" Buick V6, which was installed in such stellar machines as the Skyhawk. The funky "odd-fire" crank setup made the engine rough, but reliability was very good (and The General eventually loosened the purse strings enough for his engineers to make a smoother "even-fire" version).
Keep fast-forwarding, and you'll find this engine surviving through the Malaise Era, through the Oliver North Era, and all the way up until the present day. Displacements have come and gone, but the 3800 aka 231 has proven itself to have the real staying power; not only did a turbocharged version power the legendary Buick GNX, but Eaton superchargers started getting bolted on during the 90s. What was the most powerful factory Buick V6? Well, that depends on whether you believe The General's numbers about the GNX! Hate away, you pushrod-phobes, but you're looking at a success story.
[Wikipedia, image source here]