Was thinking of running E85 since it's cheap and available 1/4 mile down the road from me. Wanted to get some people's thoughts I have no experience with this. Car is a 68 442 with 10.1 comp, cnc aluminum heads, voodoo cam 268/276, headers, 800 cfm Edelbrock.

 

I have researched this as well.

Running E85 really shines on forced induction engines (turbo, supercharger) due to the high octane rating. It’s basically race gas octane for pump gas price. The problem is it takes about 30% more fuel volume for the proper tune. That might create fuel delivery issues. E85 is also very corrosive, it’s hard on rubber lines.

I have no clue what’s involved in recalibrating a Edelbrock carb for E85. Plan on replacing the fuel pump, all the rubber lines, for E85 compatible parts. Definitely add fuel treatment if you store the car for a long time, and park it with a full tank to help prevent condensation.

 

That's good advice. I store each of my vehicles and ICE equipment w/ topped off fuel tanks just prior to winter storage.

 

E85 requires a completely different carb. Even if you change the jets, the internal fuel passages are not large enough to flow the required volume of fuel. You also need to change any materials in the fuel system that are not compatible with E85. Compression wants to be bumped up to take advantage of the E85, and obviously timing curves will be different. And once you do this, you can only run on E85. This isn't a "dual fuel" conversion.

 

Correct on the compression. But if you’re suggesting more advance with E85, that’s not what I’ve found, Engine masters did a test and got the same results I did. It didn’t want/require more timing
To some degree octane rating is octane rating. So if you have a combination that requires higher octane then it’s a great, cheaper fuel. Otherwise it’s just added maintenance that some don’t want or need to fool with.
Note; I’m redoing my own 350 in my ‘72. It’ll be flex fuel, coil on plug with 10.5:1+ and iron heads. In this case I expect the E85 to be at least some benefit, especially here in the Florida heat. Plus it’s readily available around here and .80/gal cheaper than 93 as well.

 

Cool setup, Mark. Will you be using a sensor in the fuel system to automatically adjust the injector duty cycle based on fuel?

 

Yep, regular GM sensor hooked to the AEM Infinity ECU. Plus their flex fuel tables are already setup. Almost plug n play.

 

Thanks for the info guys. Looks like I'll be sticking to 93 octane for now.

 

Finally a post I can contribute to instead of being the newb. I have a '68 442 and live in Colorado at 7600 feet. My car came with a pretty stock 455 and it was such a dog I ended up buying a race motor that was about 11.25:1. Motor had a very large cam and a 3500 stall, which didn't fit my needs. I had mark (CutlassEFI) order a full roller assembly and custom grind Lunati cam that was very driveable and has about 10" vacuum at idle for the power brakes. 93 is very hard to find here although e85 is everywhere. I decided to keep the higher compression and convert to ethanol. New carburetor, TanksInc tank with in tank pump, fuel lines, etc. Very straight forward process although running all new larger fuel lines was a giant PITA and I would not do that again without taking body off of frame. One issue I have found is that e85 is always a slightly different ratio of ethanol to gasoline. I had motor tuned with actual 85% ethanol e85 from Bandimere Raceway, although filling up at the local gas station I have found the percentage of ethanol varies from 55 - 75%. It's hard enough keeping a carbureted engine in tune with all of the elevation change here and throw the variability of fuel in there it is impossible. All this just to say, I think you are making a good decision sticking with 93 octane gas.