Chevy V-8? The only holes that clog up routinely are the ones on both ends of the cylinder heads, and you can reach them by removing the valve covers. Just poke them clear with a piece of dowel rod and scrape the gunk away that's accumulated under the covers. While you're in there, replace the valve guide seals. One with enough mileage to clog the drain holes probably has totally worn out guide seals to go with it, and it will smoke like a freight trrain every time it's started. After the worst of the crud is removed by hand and the valve covers are back on, add a quart of kerosene to the oil and run the engine for 30 minutes at 1,500 RPM. DON"T DRIVE IT! Any load on the engine with solvent in the oil will burn rod bearings.
Jerry
