On Thu, 29 Nov 07, HK wrote:
What steps
are taken to build up these engines to take that sort of constant high
rpm stress?

Install brass freeze plugs and you're done.
I had an OMC once. I bought a short block (chevy) from an auto parts
store, they replaced the freeze plugs (they sell a LOT to nautical
types), and as far as I know, that engine is still pushing that boat.
I sold it maybe 15 years ago.
From my experience, it's the drive trains that give most of the
problems. Not the engines.

Rick