Has anyone successfully bored a 318 to 4.04?

alpha13 said

I have been wondering about this too. I have a set of 4 inch flat top pistons for a 360 that I want to use in a 318 to duplicate HotrodDaves super duper mpg 318 build. Would it be safe In a Daily driver or would the 9.5:1 compression crack a cylinder?

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I've seen and read HotRodDaves build. I just would not do a direct copy though. Heres why.

Less cylinder boring out means a smaller engine. It is harder to get better mileage from a larger engine. While the overbore should only be done to get a great start, do a min. overbore to do so.
It also means a thicker cylinder wall. Less flexing of the cylinder even though it is a low powered engine. (AKA less stress) A thicker wall is longer life.

Dave did well with his build.