Make sure your oil filter has a check valve. I'm not a mechanic, nor do I have any hard data to back up anything that I say, at any time*, but it makes sense to me. You could take out your spark plugs every time you start it, crank it untill you have oil pressure. That takes a lot of the stress off of your bearings and it would probably greatly extend your engine life. But first and foremost, use a quality motor oil. I personally don't think viscosity really matters that much unless you live in Maine or Guam*, but I do know that cheap oil is false economy. I use Mobil 1, the one they recomend for older cars, it's middle of the road viscosity rating I'm thinking I'm good to go.
When I went back to Caly from Arkansas, I developed an oil leak somewhere in east Texas. When I pulled in at a station in Amarrillo (man I really hate that city, boy I tell ya what) to get gas, I was 2½ qt. low on oil. No telling how long I had been driving at 80+ MPH on I-40 lower than the line on the dipstick. I firmly believe that Mobil 1 not only got me home all the way back to L.A., but it was several months before the inevitable engine falure caught up with me. 20k miles. I'm totally sold.
I had a 78 Chevy Luv when I was in H.S., and I put the cheap oil (parafin based) in and it spun a bearing in 2 months. I hope this helps