Classic/Antique Car Repair: compression ratios, compression ratios, compression ratio

Question
could i still use 87 octane with a 9:4:1 compression ratio?

Answer
Richard;
   HI - well  you will not get the same performance , but you can use it if the car runs ok on it , or you can add a can of gas treatment to each fill up , try it and see how it is , if you do not hear any pinging and it runs ok than go on and use it as gas prices are crazy ....