race on E85 fuel

it will have to be tuned to run on it.

what do I have to do with the carb I know e85 takes 25-35% more fuel

Bigger jets in carb,advance timeing,readjust valves.adj carb,air to fuel flow has to be right with this fuel.

E85 will ruin your carb and fuel lines, also ethanol doesn't produce the same energy when burned in an engine, not recommended at all.

don't forget upgrades to the cooling system...the fuel has tendency to run lean and therefore burn hot creating the possibility of internal engine damage.

Really it depends on how you have your Mustang built. The alcohol content in E85 is awesome at making power with the right setup. We're building a 650rwhp Camaro designed for E85 right now. You need to worry about detonation. There is a fine line where to run your fuel mixture (rich/lean). The leaner/hotter the engine runs the more efficient power youll be making, but the probability of detonation is higher. A carb engine is going to be a lot harder to reliably modify for E85 than a fuel injected engine due to lack of sensors/information available as to how the engine is running. Also due to the alcohol content in E85 youll need to rerun your entire fuel system as the E85 likes to destroy seals, lines, etc.

get an E85 or alcohol race carb, or rebuild it with alcohol safe components, try looking in summit i think they have a kit to change your carb over