1961 Smoke and oil light on

[74 Harley]

Ok next trick. Remove both valve covers and then the rocker shafts. Place a straight edge across the top of the valve stems. Look for any stems that seem high, especially if it's on a cylinder with lower compression.
Report back with pictures of you can.

 

[Ward 57]

Drive it. Add a quart of cheap ATF and watch how fast the oil turns black. The lifters might even quiet up after being flushed.

What is it with all these different uses for ATF? 69yo shade tree mechanic and never knew it was basically as good as the canned stuff as a lubricant/cleaner.

 

[Critterpainer]

What is it with all these different uses for ATF? 69yo shade tree mechanic and never knew it was basically as good as the canned stuff as a lubricant/cleaner.

ATF is very high detergent and helps flush residue out of the crankcase and out of restricted passages. Not good as a lubricant for bushings but better than dumping kerosene or diesel into the crankcase.