The Vette's engines grew stronger as the muscle ... and upgraded suspension was limited to a run of only 12 cars. LS6 'Vettes rarely come available for sale and usually go for around $150,000.

Unrestored, highly original, and numbers-matching, this 1970 Chevrolet Chevelle SS 454 LS6 unexpectedly failed to set a new ...

but a retractable roof turns an LS6 into a super-rare rig. Again, precise production numbers are unavailable, but Chevelle experts agree that only 12 to 25 drop-tops got the 450-horsepower engine.

And it's pretty clear why many think LS engines are so special. They're powerful, durable, reliable, easy to service, and cheaper to tune, but none are more infamous than the LS6. The story of GM ...