Ford carb 460 Octane?

[iboaterlurker5]

Local gas station has 90 unleaded ethanol free gas and 93 unleaded with ethanol gas.

Old Ford 460 marine carb engine. RPM Max: 5000 RPM, Compression ratio 8.35:1, 160F degree thermostat, elevation around ~500 ft, ambient temps around 80-100F. Manual says I should run 93.5 leaded gasoline.

For this low compression that seems unnecessary and I would like to run ethanol free if at possible for the carbs and fuel lines sake. No knock sensor on the engine (carb), so I obviously don't want to ping.

Run 90 ethanol free or 93 with ethanol?

 

[Earl Cordova]

If I could get ethanol free, that is what I would use.

 

[Bondo]

Ayuh,..... I put nothing but ethanol free gas in all my boats, 'n small engines,....

That motor would be happy on 87, or 89 octane, the 90 will be no problem,....

 

[Lou C]

Local gas station has 90 unleaded ethanol free gas and 93 unleaded with ethanol gas.

Old Ford 460 marine carb engine. RPM Max: 5000 RPM, Compression ratio 8.35:1, 160F degree thermostat, elevation around ~500 ft, ambient temps around 80-100F. Manual says I should run 93.5 leaded gasoline.

For this low compression that seems unnecessary and I would like to run ethanol free if at possible for the carbs and fuel lines sake. No knock sensor on the engine (carb), so I obviously don't want to ping.

Run 90 ethanol free or 93 with ethanol?

What manual said to use leaded gas? Must be a REALLY OLD one!
I have an original OMC owners and shop manual, they used the Ford 460 for a few years, and they said to use 89. just to be on the safe side I'd use 89 though where I am the gas docks sell only 93. Overkill but you'll never have detonation.

 

[iboaterlurker5]

What manual said to use leaded gas? Must be a REALLY OLD one!
I have an original OMC owners and shop manual, they used the Ford 460 for a few years, and they said to use 89. just to be on the safe side I'd use 89 though where I am the gas docks sell only 93. Overkill but you'll never have detonation.

It is the original manual from the early 80s lol. Berkely jet owners engine manual for 302, 351, and 460. I think i will just run the 90 ethanol free.

 

[bruceb58]

If it pings, you can always retard the spark a bit. I doubt it will but keep that in mind.