Ls7 454 e85 conversion

[txmike06]

I have a ls7 454 in a 68 corvette I've been running on 100LL. I would like to switch to something where i can go on car cruises and not have to carry a can of extra fuel around with me just in case. E85 seems to be my solution. 

The ls7 is an old crate motor with 12.5 compression. The casting date on the 990 heads is 1980 so it should have the induction hardened valve seats. It has the factory iron valves in it though.

My main questions are what size fuel pump should I go with and how far will the factory 3/8 steel lines carry me? The guy who is building me a e85 carb said he would leave the pump and lines alone and just not race it and it should be fine but I'm curious what other people think.

Some of my other questions are I've read about the fuel getting cold enough to cause condensation inside the cylinders and heads and should I worry about the valves rusting? Also if it has induction hardened seats will the e85 have any adverse effects on them? It's a solid cam so I figured I would check the lash and if it has a lot of extra I would pull the heads. I was thinking i could throw 5 gallons of the 100LL in a tank and maybe that would give the top end some extra lubrication. How many people use the vial e85 testers and how accurate are they opposed to a flex fuel sensor? 

Thanks. 

[triplenickel]

If you're not racing it, your fuel system will probably suffice. Maybe go with an alcohol compatible pump & lines if you're happy with the E85. If you're concerned about valves & seats, you could add some top lube. You may also consider adding gas to E85 to bring it to E70. This % will still be safe for your compression & will lower the demand on your fuel system some. E70 will require leaner jetting. Ask your carb builder how much leaner to go. The extra gas should also help the top end. If you're driving it a good while & getting it to 170-180 degrees, condensation shouldn't be a problem.

[triplenickel]

Note about top lube: I've heard that some top lubes are separating from the e85. Make sure it's for use with ethanol & test it with a jug of fuel to see if it separates. Some people use Marvel Mystery Oil.

[bigydaddy]

been running E85 in my 454 ls7 since 2010. Runs fine car is way more fun to cruise with on cheap fuel. No downsides yet. Oly problem is if it sets for more the 10 days, some times the accel checks get stuck. If that happens just tap them with the plastic end of a screwdriver while holding down on the pump arm to free them. Been on a holley black pump with a bypass regulator, no top lube. Have fun

[txmike06]

Jul 11, 2016 9:09:02 GMT -5 bigydaddy said:

been running E85 in my 454 ls7 since 2010. Runs fine car is way more fun to cruise with on cheap fuel. No downsides yet. Oly problem is if it sets for more the 10 days, some times the accel checks get stuck. If that happens just tap them with the plastic end of a screwdriver while holding down on the pump arm to free them. Been on a holley black pump with a bypass regulator, no top lube. Have fun

Are you running a bigger fuel line all the way from the tank or just going with a factory 3/8 steel line?

[bigydaddy]

the car had -10 line from cell to pump to regulator, then ran -6 to each bowl of carb. Bought a bypass regulator and ran a -8 back to the tank for bypass. have been running a cheap holley black since 2008. Hope this helps.

[bigydaddy]

also motor is now a 12.5/1 489 625 hp. Great to be able to run cheap fuel. was $ 1.55 gal last week