1934 Ford

I have recently inherited a 1934 Ford from my dad who recently passed. The car is a lot of fun to drive and gets a ton of attention but I'm running low on gas and am concerned about putting the wrong thing in the tank.

I've been reading up on what other people think and it seems like some say it's no problem to put in unleaded and others say it's dangerous.

The vehicle is not stock meaning, it has been upgraded with anti-lock brakes and I believe an automatic transmission. It has a stick but the stick only has P D R 1 2 so I'm assuming the fuel system has been modernized too but I have no idea how to validate my theory.

Anyone know how I can validate the proper fuel so I don't damage the vehicle?

Thanks!