I have always changed oil and filter at 3000 miles.Works for me.Seems like cheap insurance.I used to work with a guy who had a mid 60s Chevy pickup,six banger.He never completly changed his oil,at 3000 miles he would change the filter and add 1 qt.of new oil.He had well over 100,000 miles on it and it ran good.This topic was on here a few months ago,and everyone seems to have a different idea.As for me I will go on changing mine at 3000 miles.
