That is a rather difficult question to give a definate answer to but here goes. If you can still get 93 octane gas where you live, you can try it and take the car out and drive it until it is good and warm then start putting a load on it such as a pull up a hill or accelerating slowly. Don't go to high in the RPMs. Listen for any valve clatter, I know, hard to hear in one of these things, but if you have iron heads on the engine, you can use that pump gas for normal driving. All we can get out here is 91 octane which is more like 88 actually. With my 11:1 compression and the iron heads, I can back my timing down just a little and drive the car fine as long as I don't get on it. Otherwise, lots of valve clatter. With my aluminum headed stroker and 11:1, I really don't have much problem with pump gas, but still use the 110 leaded racing gas in them if I am going to be running hard. Higher octane than you actually need won't hurt it, but you will be wasting money. I use an additive when I am out away from my barell of racing gas called Fast Forward that works with gas and alcohol. It has worked well for me. And from time to time, I add 5 gallons of the 110 racing gas to my 65 Comet with the stock 289. Makes the gas mileage a lot better as this crap we get for gas doesn't burn well at all. But it doesn't hurt it at all. If you have hardened valve seats, the pump gas is ok if the compressiojn isn't to high. Mainly the lead acts as a lubricant. Another thing that you could do is take a sample of the gas that is in the tank and have it analyzed to see if it is the racing gas. Here the 110 is bright red. Pump gas is not a bright color here, just a sort of dull reddish. Sorry to hear about your Father.
Ron
