45ss con rod chamfers

[jimi]

Xmas project
I'm rebuilding a 45 ss and only have one original con rod (no oil holes).

http://www.apba.org/sites/all/files/documents/2013_SST45_TECHNICAL_SPECIFICATION041013.pdf says "... chamfering the oil holes..." is allowed. Another blog/forum... suggested that without the chamfer the fishing engine rods break.

My question is how big a chamfer and how best to make it. I was thinking about using a dremel with a conical stone, high speed, low pressure and lots of oil to make the surface as smooth (micro crack free as possible).

Any one have experience with this?

[modifiedoutboard]

The pre 45ss racers used 50hp fishing motors (pre 1980) and had problems with bottom end failures.
The later year rods and cranks are mechanically stronger and did not inherit the same issues.
When OMC made 45ss concerns from older engines were addressed on the new engine.

We ran stock fishing rotating assemblies above 8,000 rpm with out failure or signs of fatigue.
Also note that mercury makes a stronger rod bolt that is dimensionally identical to the OMC rod bolt.
We never used those but non cryoed OMC rod bolt threads showed tell tale signs of failure after a few races.