You have to look into your car's manual to find that out ( provided you still have it ) other wise you have to ask around, but usually, japanese engines require a minumum of RON 95.

If you use the 92 stuff, you would probably hear a lot more noise coming from your engine when you go up slopes ( knocking ) and might suffer engine damage ( worst case scenario ).

Your engine should be quite economical.

and what makes you think his car thats at least 30 years old has one ?

Leaded petrolis banned all around the world. RON rating has nothing to do with having leade content or not.

Fuel injected cars can run RON 92 petrol but then you will experience a drop in power due to ignition retardation to prevent knocking.

Your old corolla has a pushrod engine if I'm not mistaken. Check all the tappet clearences and if your engine has never been overhauled for the past 10 years I think its high time you do so.

If you engine was meant to run on leaded petrol your valve seats have probably been worn so badly they have sunken in. So check them too.

Old cars used to have lead added into the fuels as a cushion for the valve seats as the valve seats weren't hard enough to withstand the pounding. Without lead, the valve seats would become so hot knocking would occur.

Then in the early 80's lead was found to be cancer causing element. They banned it in all products from cups to wall paint and yes petrol.

All engines before that time had to have their valve seats changed to withstand unleaded petrol.

So when you use unleaded petrol on a leaded cylinder head then you have to by an additive to mix by the tank. Otherwise you can send it to certain companies that change valve seats. People who deal with classic cars should have contacts for these companies.