Inliners International Forums General Discussion Engines Greeting with my 250 questions?

What was the difference? My nova is a 1978. I seen this on a chart:

LD4 Chevrolet 6 cylinder
The LD4 was a 250-cubic-inch (4.1 L) I6 engine produced strictly in 1978.

What was so different in 78? I know they did the Integral head from 75 and up. Why does this chart say that? Was there something different in 1978 on the 250?