65 396/ 425

[Walter F.]

Is it true the one year 396 425 horsepower in the Corvette was basically the Mystery motor raced at Nascar in 1963 ? Was this a better performer then the later 427?

[Joe L.]

Re: 65 396/ 425

Is it true the one year 396 425 horsepower in the Corvette was basically the Mystery motor raced at Nascar in 1963 ? Was this a better performer then the later 427?

Walter-------

No, they are not the same. The "Mystery Motor" was a Mark II big block. This engine had cylinder heads that were similar to (but NOT the same) as those used on the Mark IV 396 first released midway through the 1965 model year. I believe the block was derived from the Mark I big block (i.e. 348/409). So, what was the Mark III like? We'll probably never know as it was never produced.

If you mean was the 396 a better performer than the 427, the only significant difference between the two was a difference in bore size-----4.094" versus 4.250". I think the strange 4.094" bore size of the 396 was an effort to stay under 400 cid and/or an effort to hit 396 cid "on the money" for some sort of marketing purpose.

[Larry E.]

Re: 65 396/ 425

Found a picture of the "Mystery Motor">1963 Daytona Pole. Controversy surrounds the Chevrolet Mystery Motor that Junior Johnson used to stomp the field in the first 100 mile qualifying race at the 1963 Daytona 500.