Clicking In The Engine

A little info for a newbie. Your slant has "solid lifters". Those require regular adjustment, at least every 40K mi. A slight ticking sound is normal. People call that the "sewing machine sound" of a well-running slant. In the 80's, slants changed to "hydraulic lifters", which never need adjusting. Most cars today are hydraulic. Solid is not necessarily bad, and is actually preferred for race car engines. My 80's Mercedes' have solid lifters.

BTW, the slant six is considered by many to be one of the best, most reliable engines ever made. That really refers to the block and crankshaft. The carburetor and ignition can cause continual frustration, unless you repair or upgrade. The heads and manifolds are not good for high air flow, unless you add a turbo, in which case a few have realized 11 sec qtr miles.