Straight 40 weight oil is going to be a bit thick for cold starting in yankee-land. I'd recommend 15W-40 Diesel rated oil, as it flows like a 15 weight when cold, and lubricates like a 40 weight when hot. BTW, the "W" in multi grade oil nomenclature doesn't stand for "weight"- - - -it means "winter" since the cold flow characteristics are measured at freezing temperatures. I agree with your builder's opinion of hard exhaust seats- - - - -they're only necessary when running "dry" fuels like LP or CNG.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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