Can I use motorcycle engine oil on automobile?

Back in the early 1980's I used motorcycle oil in my 1969 Plymouth GTX, never had a problem, Here is why, automotive engine oil was being regulated for heavy metals like copper and zinc, so they were reduced and eventually removed from auto oil, but not motorcycle oil, so I used that for improved friction protection in those days.

Now a days most automotive engines are using roller valve trains, that protection is not as critical anymore, but I still use Valvoline VR racing oil, which is loaded with zinc.

If you have any gas engine that is not a roller lifter type, you should at least be running a zinc additive in your oil.

The main difference is that motorcycle oil are used for the engine, gearbox and clutch while automotive engine oils are "specialized" for the engine. Therefor the motorcycle oil needs certain additives (mostly wear protection) that the engine doesn't need, while the automotive engine oils contains more friction modifiers (low friction, optimizing fuel usage and heating) that are unsuitable on an motorcycle clutch, as a wet clutch needs a defined friction.

Bottom line: Use the right automotive oil for cars and use the right motorcycle oil for motorcycles

A concern might be the additive package in the specific oil you use. Some of the additives that used to be common in auto oils affected the catalytic converter so the levels were heavily restricted. Motorcycle oils might well still have higher levels of these additives.