I was out in the yard working my year long fix up project (which has taken the place of the Camaro project during the heat and humidity), looking at the state of my Walnut trees and a lady drove up in her SUV and stopped and wasn't sure how far the next gas station was. I'm in the boonies but urban adjacent, and it was a long haul to the next gas station so I gave my lawn mower gas to her so she could make it. I noticed her cap was yellow and said E85. I hadn't gave thought to E85 in a long time. Has anyone built a Chevy inline 6 to run on E85 exclusively to take advantage of a higher compression with its higher octane?

I know manufacturers try to scare owners off from "evils" of E85 in a car intended for 87oct Regular "E10". I'm not really sure how corrosive gasoline fuel tanks, fuel lines, fuel pump, carb and valves are to the "evil" Ethanol? But it wouldn't be uncommon to replace all of those on a build anyway.

E85 vehicles are computerized flex vehicles that are designed to run on 87oct but sense which mixture of Ethanol is flowing through it and adjust richness and spark accordingly to run with an 87oct compression ratio. And as such you never get the full benefit of the E85 octane. If you had a consistent reliable access to E85, you could build a non-flex E85 only engine, but I haven't noticed anyone doing that? For me, I'm in corn country with corn rows as far as I can see from desk, and surrounded on all sides by it.

yes you can.

Though I'd strongly suggest using MS efi and its ability to sense the fuel content mix as the E content can vary and induce knock issues.

I'm glad I'm not the only person wanting to do this.

I am running a Holley Dominator ECU with a Continental Flex Fuel sensor. It's not up and running yet but I am working gathering all the parts first.

Long time since my last post here.

About E85 use. It takes a while to corrosion takes place. I know that because here, in Brasil, we use E100. I use it on my everyday comuter, which is a 2009 GM.
Ethanol wakes the 250 up. These engines came with 10,5:1 stock from the factory to use ethanol only. This was in early 1970´s. With carburetors!
With today´s tech, things are getting easier.

You have to upgrade every piece of the fuel system to ethanol tolerance like really modern cars. E85 will eat any older solder joint, hose, liner, pump diaphragm, gasket, or seal if left in long enough, and the corrosion makes white dust out of metal, which then clogs your filters and small passages.

No. It will not. I´m still using gasoline only carbs without any treatment. Not a single problem, dirty, dust off. Even the electric pump is for gasoline only. Never had a single problem.
But here we use sugar cane alcohol. Don´t know about corn alcohol. Anyway cannot be that different.
I say go ahead mate. Do it if you feel like.

Of course not, because you said so.
"I don't think I have a problem, therefore there is no problem".
So glad you cleared that up.

The underlying chemistry of materials compatibility can be a bit mind boggling - but in the end it comes down to permeability: if a fuel or solvent can permeate the material (pump diaphragm, fuel line, gasket, glove) it will eventually break it down. Add pressure (like in fuel injection) and even historically proven materials can begin to fail.

The folks over at efunda present o-ring material compatibility data in tabular form making for easy comparison. Take natural rubber - it is rated 4 for use with ethanol; but rated 1 for use with gasoline - making it poor choice for blended fuel.

As for the compatibility of ethanol with metals - it's really not the ethanol that is the problem - it is the fact that (like brake fluid) ethanol is hygroscopic. Both literally absorb water from the air. In brake systems the key is to keep the air out as much as possible - and to flush the system regularly to discard the water logged fluid before it can rust components.

The same is true with Ethanol (end even more so Methanol) based fuels. This article over at The Shop Mag discuss the problem of corrosion in parked vehicles.

Seems the more a vintage vehicle is driven the better it will tolerate ethanol based fuels. But if one must park it - flush it.

I was surprised to see how many ethanol pumps there are in my area, makes a guy think! But for sure, stock49 brings up some valid considerations, especially if she's a recreational vehicle and not a DD!

I know the original gas tank on my 53 pickup is soldered together. I'm not an expert but a special said the biggest problem is that E85 varies so much in octane levels between different makers and even batches.