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I love my Chevy Chevette!
Posts: 2
Joined: 08/17
Posted: 08/24/17 03:08 PM

I happened across this article from 2006; "Mark IV Big Block Chevy Engine - The Mark of Chevy Power Where Chevy Muscle Really Lives" by Paul Zazarin

In the article, he makes some factual errors regarding bore and stroke:
"In 1970, the Mark IV was treated to a 0.24-inch bore job, taking it out to 4.00. With the 4.25 stroke unchanged, the new engine displaced 454 ci."

Actually the 396 big block bore was 4.094"  which was bumped to 4.124" (+0.030")  for the 402.  The 427 was 4.250" and had the same stroke was the 396/402 at 3.760".

The 454 was made using the 4.250 bore and increasing the stroke from 3.760" to 4.00", that is, slightly less than a quarter inch longer.  

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