Running 91 Octane No Ethanol Fuel in an older PCM ?

[VTCharlie]

I can now get 91 octane fuel with out ethanol here in Vermont ( for a While ).I have been running 89 with ethanol using startron. It is a stock 351 92 196.My question is there any down side running higher octane in this engine ? deteonation etc.I really like nor running ethanol and don't mind the extra cost just want to make sure the engine will like it with no down side issues. I have about a 50/50 mix now nad seems to be running great. Thanks for any info. on this.

[surroundsound64]

Run the high stuff. You won't hurt anything.

[mdvalant]

Just sold our '90 Nautique to a family friend. It has 1350 hours on it all ran with 91 no ethanol. (We always added lead additive to it though)

[surroundsound64]

Or if you can afford it, go to the local airport and buy 100LL. It'll run great on that too, speaking of lead additive!!!

[horkn]

I have run e10 in my boat nearly exclusively since I have owned it. That goes back to about 2002. It's a 78 martinique with a 351W PCM in it. You won't have any issues running e10, even 87. I have decked gt40P heads on it too, no problems at all, even with more CR than even GT40's have. The low Compression ratio, larger combustion chambers of non HO pre GT40 heads is even more tolerant.

People worry far too much about ethanol. I've had to use it in everything I own for about 20+ years now. Have not had a single issue.