A Question about oil in a summer car

So as the name suggests I have an older car that I only drive during the summers. It's a 1981 Buick Century with the 231 v6. I dont really know how far it has travelled since the odometer has turned over. It's a prett rare car, only 5 in europe. I got it about 3 years ago, by then the car had been sitting in a parking lot for aprox 7 years.

Now to the real thing. I've had a bit of valvetrain noise and some general worry that the oil I'm running isnt really the best. I currently run it on 10w-30, Mobil 1 and I change it every year, althoug I change before I take out the car from hibernation. I dont drive much more than a couple of a hundred miles.
I've heard that running 0w-40 with more zink would be smarter but I just want to check with poeple who knows for sure.

And if there is something else you want me to change to make this car last as long as possible.

Quick side note, I have never changed the atf oil out of fear it would start slipping, the diff oil has been changed once during the early 2000's



Thread starter
The # of miles you drive it; Seriously, nothing kills old stuff faster than lack of use.
Yeah you right, the reson being I just got my licence then covid happended and all the car meets and such where cancelled. I hope this year I could drive it more often