Currently am in the process of doing a cam swap on my 2000 Z28. I am chugging along just fine but have a question regarding the oil pump. I went ahead and got a Melling 10295 oil pump, when I was removing the old oil pump I noticed the o ring stayed inside the body of the pump and not on the actual oil pick up tube. Being a dumbass bonehead I seated the new Melling O ring inside the Melling pump body instead of on the pick up tube first.

The pickup tube seemed to bolt up fine to the pump body, it looks flush and not sitting cockeyed. But i'm wondering if I should just drop the oil pan down again and check the O ring. In addition can I use a GM oil pump o ring or does it have to be a Melling o ring since i'm using a Melling pump? Thanks everyone for the help.