I'm on a budget here on the little ridgetop farm. Got 2 old Fords with big diesels that take lots of 15W40 motor oil, three old tractors (1948, '68, and '74), and a 1968 CASE 380 hoe/loader. I buy whatever's on sale at TSC or Rural King, cause I can't afford $95 for 5 gallon at the independent...