If you want absolute confidence, search the auto gas STC suppliers' lists to see if an STC is available for it.
Having said that....
I've been running E-free premium auto fuel in 160 HP O-320's (different -dash numbers) for over 20 years with no ill effects, except that caution must be used if you're in the USA & there is 'winter blend' fuel sold where you live. Winter blend in hot summer temps is not a good thing, due to increased vapor lock risk.
Do note that I run *premium* grade auto gas. The higher compression of the 160 HP O-320 doesn't seem to like regular grade very much.
Charlie