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Upgrading to E85... what all do I need?

631 Views 3 Replies 3 Participants Last post by  FmrStrtracer
I'm looking at upgrading my entire fuel system, in my '77 Mercury Monarch. I can handle the 30% loss in fuel economy in exchange for the increased octane/timing advance/hp/environmental factor that E85 offers.


Motor is the stock 302, with a 2bbl carb on it. I *believe* that it's 8.5:1 compression. That's going to get replaced with a dual plane intake, and one of Holley's E85 4bbl carbs, probably around 600cfm, maybe smaller.

What fuel lines, fuel pump, fuel filter, etc. do I need to get?

I have already considered buying a new fuel tank, since it's only $167 shipped, and won't have all of the sludge that this 32 year old car has built up in it.


I'm not building it to be some radical hot rod, but I do want the advantages of the E85, and it's available at most of the gas stations here.


Any help?
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Chefasaurus said:
I'm looking at upgrading my entire fuel system, in my '77 Mercury Monarch. I can handle the 30% loss in fuel economy in exchange for the increased octane/timing advance/hp/environmental factor that E85 offers.


Motor is the stock 302, with a 2bbl carb on it. I *believe* that it's 8.5:1 compression. That's going to get replaced with a dual plane intake, and one of Holley's E85 4bbl carbs, probably around 600cfm, maybe smaller.

What fuel lines, fuel pump, fuel filter, etc. do I need to get?

I have already considered buying a new fuel tank, since it's only $167 shipped, and won't have all of the sludge that this 32 year old car has built up in it.


I'm not building it to be some radical hot rod, but I do want the advantages of the E85, and it's available at most of the gas stations here.


Any help?
Not to rain on your parade or anything, but you won't see any measurable gains unless you're changing your C/R also. That's where the benefit of E85 kicks in, as it's somewhere around 105 octane? (don't hold me to this, as I am inexperienced in this area). The gains will come from a compression increase, not from the fuel itself. Compression change implies new heads, which in turn implies a new cam to take advantage of the higher compression...etc, etc. Maybe with the new intake it'll net a couple more HP, but don't expect anything too crazy to happen.

That being said, I don't think you'll need a new filter, lines, etc. You'll just need to modify your carb. to be able to handle the change in the A/F mixture.

Just my $.02.
I'm not opposed to getting some higher C/R pistons and heads.


The bottom end, I could splurge a bit on. Heads start to get expensive... looking for a fairly low-budget build... one that I can buy all the parts piece by piece, and then put it all together by the end of summer.


Basically looking for around 400whp, that I can run on E75 (during the winter, they lower the octane rating to about 100), and E85 in the spring/summer/fall.


I was under the impression that E85 would eat through the old rubber fuel lines, and the stock fuel pump can't pump the extra fuel that's necessary?
You are correct, all rubber fuel line will need to be replaced with alcohol compatible line, along with an alcohol compatible fuel pump.

Youre not going to make 400hp without replacing the heads.
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