About to the first oil change since engine rebuild, got a couple questions.

[mud.man.rj]

I break an engine in in the first run, so 15 -20 minutes, change oil, put on about 300 kms, change oil then every 3 times a year with low kms on it just to keep the acid level in used oil down, usually ends up being 1,500 kms. I may change it a bit to often but better clean than not and cheap insurance, also use a botle of GM additive on every engine, every oil change. Not much for price if synthetic. usually run 5w30 in colder climate and 10w30 the rest of the year.