Page 1 of 1
56' 331 Hemi - octane gas?
Posted: Thu Jul 17, 2014 10:03 pm
by flynnstone
I just picked up a 28 Ford with a 56 331 Hemi which originally was in a grain truck. It's running ball&ball carbs and the truck intake.
Just curious what octane fuel is required for this motor?
Re: 56' 331 Hemi - octane gas?
Posted: Fri Jul 18, 2014 7:45 am
by George
According to this site it is officially 7.5 C/R, and some hemis, when measured, have measured up to close to a full point lower than posted C/R, so it could be anywhere from 6.6 to 7.5. Should run on 87 w/o any problems. If you're where Sunoco sells 85 it would probably be good on that.
Re: 56' 331 Hemi - octane gas?
Posted: Sat Nov 22, 2014 3:31 pm
by Rob
It would run on 79 I bet. lol
Re: 56' 331 Hemi - octane gas?
Posted: Sat Nov 22, 2014 7:58 pm
by George
Rob wrote:It would run on 79 I bet. lol
Probably. hemis can run a point higher C/R on the same octane as a wedge, so what octane would be needed on a 5.6-6.5 wedge engine?