SHELBY GT 350 Member
Joined: Jan 2011
Location: Central Massachusetts
Once a year is probably fine, but I would do it twice -- once immediately after you take it out of storage, and again about half-way to when you put it back. Yes this is overkill, but not a real big deal.
The Mobil 1 should be more than good enough. You could save a few dollars by going to something cheaper, but I would stick with the Mobil 1.
For grade (weight) I would use whatever it says on the oil fill cap for normal street use, and I believe that is 5W-20. If you have any major high RPM and/or high temperature use in mind (like on a road track) then I'd go with 5W-30.
Do you find the oil minder telling you to change it every six months, regardless of mileage? I haven't actually tracked it, but I'm pretty sure mine does that. I think it tracks mileage and type of use and will tell you to change it based on that, but it will also tell you to change it every six months, regardless of mileage.
| 2010 GT coupe | Daily Driver with some Steeda and GT500 take-off stuff for the occasional track day