If you have built and run more motors than your builder has, do as you wish.[QUOTE]
Never said I was an engine builder; just trying to figure out the "why"
If he has built and run more motors than you have, follow his advice.
I was just basing my quesion on other posts in this forum basically saying 10W30 should be fine that there is no reason to run a single weight oil (30W).
Thanks for the input.