No marinas sell anything higher than 87 octane here. I'm looking for a quality and quantity octane booster. I'm tired of buying small, ineffective bottles. Anyone have any suggestions about buying quantities larger than the small bottles and better quality as is typically available at local O'Reilley's/Auto Zone type stores.

Thanks

The bottles of octane booster at the auto stores are useless. What octane do you need for engines???? Best option is to mix in high octane race fuel.

i agree with griff on the race fuel. i do mix toluene with my pump gas for my high compression snowmobile. you might want to look into that. it bumps 91 up to around 105-108 but i am using it on a 2 stroke snowmobile so im not sure how it would do on your boat.

what is your engine compression

A good discussion of octane boost is here.
http://www.offshoreonly.com/forums/g...ane-boost.html

Toulene or Xylene seem to be the best suggestions, but don't mix it over 20% or so.

might consider avgas from your local airport. its 100 oct and contains lead. it has worked well for me in my dirt bike for many years. usually mix it 50/50 with super (93)

isn't avgas mostly alchohol and dryers to prevent icing?

My compression is 10.5 I believe. I was told by builder to run better than 87 octane. I do have a trailer but trailering a 38ft boat with a crew cab dually and then getting into a gas station can be a bit of a challenge.

It looks like I just need to suck it up and hit a gas station every so often at a time when they're the least busy.

Wish me luck !

Aluminum heads or iron?

Iron heads with a little flow work, most of the usual stuff. Inconel/stainless valves, little bit aggressive cam, roller rockers, good springs, good pistons, parts overall pretty nice. Not a race engine by any means. Started life as a stock 502EFI. Bored + .030. Some computer mods, other engine mods as above, Stainless Marine long risers.

They've been great motors for almost 500hrs with one complete overhaul about 100hrs ago. I just don't want to have problems. Two marinas here used to sell 93 but no longer do.