Engine oil question

[docderwood]

PCM manual for my 2008 zr6 390 hp specifies 15W-40 GF-4/SM

I've been to 3 auto part stores, none of them have he GF-4 spec.

Doubt it matters but am curious what others think?

[Red57Bird]

Do a search on the forum on "ZR6 oil" and you should find a lot of threads with info.