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racefan101
06-07-2010, 07:20 PM
i was wondering how much of a difference a motor bored 40 over has compared to 30 over and could i bore a 30 over to 40? i would just need new pistons and rings also correct?

hpontap
06-08-2010, 04:41 AM
Are you asking if a .040 engine makes more power than a .030 engine, all else being the same? The answer is no. If your block does not need to be bored due to wear, it is best not to.

Hillbilly Deluxe
06-08-2010, 08:17 AM
One thing that came to my mind is - what size engine are we talking about here? If you want to bore out a stock block, why not bore it out .060 and be done with it. Most times - if it blows up, it isn't reusable anyways.

Is there a difference between stock and .060 over - you betcha.

Racingtech
06-17-2010, 10:53 AM
With the cost of a race preped block so high nowdays. Most racers will bore 30 over first and then 40, and last 60. This will allow you to use the same block for several seasons. I personaly would'nt bore a 400 small block chevy 60 over, as the walls would be kinda thin for a lot of compression. To answer your question anytime you add cubic inchs to a motor you will probably add more power, but is it worth what little gains you would see. I don't think so. Your money would be better spent in other areas if you want serious horsepower gains, like cam, heads, and intake. Good luck!