The Ford Barn

qmdv · 02-08-2023, 06:02 PM

Lets start with what I know about the engine: My dad bought it 50 or so years ago. 59AB, bored to 3 5/16, 4" crank, Offenhauser 375 heads and 2 97's. It sat for many years and I went through it. Cylinder walls rough so I went 30 over and put it in a 32 Hi Boy roadster. Unfortunately I did not check head volume while engine was opened up.

Now for the problem at hand. I put 87 non Ethanol gas in it and it rattled terrible. Drained the gas and put in some 100LL aviation fuel. Man it ran great and sounded great. So I drained out that gas and put in some 91 non eth gas and if I really get into it in high gear I get just a little detonation.

So what are my choices? I can just drive conservatively but now and then I like to put my foot in it. Maybe bight the bullet and get new heads.

02-08-2023, 06:02 PM	#1
qmdv Senior Member Join Date: Dec 2012 Location: Payette, ID Posts: 949	Detonation in my 59AB engine Lets start with what I know about the engine: My dad bought it 50 or so years ago. 59AB, bored to 3 5/16, 4" crank, Offenhauser 375 heads and 2 97's. It sat for many years and I went through it. Cylinder walls rough so I went 30 over and put it in a 32 Hi Boy roadster. Unfortunately I did not check head volume while engine was opened up. Now for the problem at hand. I put 87 non Ethanol gas in it and it rattled terrible. Drained the gas and put in some 100LL aviation fuel. Man it ran great and sounded great. So I drained out that gas and put in some 91 non eth gas and if I really get into it in high gear I get just a little detonation. So what are my choices? I can just drive conservatively but now and then I like to put my foot in it. Maybe bight the bullet and get new heads.