I may add that the "later" 348 engine heads were a little better. I can't remember EXACTLY what it was so I want atempt to explain other than it had to do with the water jackets or cooling around the plugs...Bill_B: I had a regular 62 Impala with the 327 and yep, it was a missle on wheels. Most folks could not believe how it could be so big but run so strong. That was MY secret!! BUT, like the 58 Impala, I twisted the metal up on the 62 as well. My 3 brothers and I started a junk yard back then!!!