I use 20w50 castrol in my 250 in the 63c10 tried 10w30 or 10w40 but oil pressure is to low a idle. tried other brands and the only one to hold up was castrol 20w50. with 20w50 it runs about 30lb to 35lb at idle, idle being around 950 to 1000 rpm in neutral. with a stock oil pump, tried high volume oil pump and would break dis. gear to much pressure on the gear turning the oil pump with 20w50 in it, stock pumps works fine all the way to 5600 to 6000 rpm and around 60lb of oil pressure.
super250six
