I just bought a '77 Chevrolet C20 pickup with an unknown mileage 454 (supposedly rebuilt about 10 years ago). I'm in the Houston, Tx area, where weather over the next 6 months will range from hot to hot as ****. I selected Rotella 15W-40 with a Wal-Mart SuperTech filter. The truck hasn't run for about 5 years until last week, when I fired it up on the old oil. It runs fine with no smoke that I could see. Bear in mind I paid $300 for the truck, so I'm not doing a $75 oil change.
Here's a pic of my fine ride: