Barred Boring


I need your knowledge and wisdom.
I picked up an industrial “413-1˝, with
the 2658836 block casting, the forged steel
6-bolt crank, etc.
I’ve heard that these are 426 wedge
blocks, underbored to 413. I’ve also heard
that they may be thick enough to bore to
a 440.
I’m looking for a little insight as to what
can be done with the block, crank and connecting
rods, the rest is getting replaced.
What are your thoughts on this?

To go to standard 440 bore size would
require a 0.130˝ overbore on a 413. That
would take 0.065˝ off of the cylinder walls.
Without sonic checking I’d not go near
that. Remember, thick cylinder walls make
power. A good ring seal is far more important
that a few extra inches of displacement.
For an example of what lack of ring
seal can produce, see the question above
from Jeff Fleming.
Before spending dime one on any of
this, I’d sure check both the block and
crank for cracks, M&I engines usually
didn’t lead an easy life. I’d also not even
think about using the con rods, not when
new, lighter, stronger-alloy rods are so
reasonably priced.

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