Go buy a PCV from the dealer, if that doesn't fix it then just keep topping up with el-cheapo SM rated dino.
A lot of after market PCV's don't meet the specifications properly. Always buy your PCV's from the dealer!
GM isn't the only one known to use oil... Not all GM engines are known for this, some are, some aren't. Honda has this issue with some of it's engines and so does some Chrysler's...
It just depends unfortunately!
about half a quart every 300 miles.It has 95,000 miles on it.I'm using QState 5-30 conventional.I replaced pcv valve about 1500 miles ago.Luberfiner(autozone) pcv valve
That is a lot of oil. I mentioned PCV valve because an aftermarket pcv valve can cause increased oil usage. Do as StevieC said, and see what happens. You can give A-Rx a try, or switch to a HM oil and see what happens. If you decide to use A-Rx don't use it with a synthetic or HM oil.
I would try the PCV valve first, then track oil use. If that doesn't work try some of the other suggestions. It would be nice to know what solved the problem if/when you solve it.
The 'Shortstars', like the Northstars, are 'designed' to consume a bit more oil, due to the aggressive cross-hatch on the bores.
Excessive consumption is due to stuck rings. Lots of remedies to try:
Piston soak using MMO/Seafoam/other;
Really hard 30-60 mph full-throttle 'blasts' to break the rings free.
Give one or all a try. I don't think viscosity or a HM oil will help.