While we tuned our Old-School engine to run on the E85 that's available near our house/shop, we decided to see what happens when a quality, regulated blend of E85 is introduced to our carburetors. Prism Racing is a distributor for Rockett Brand Fuels, and since Rockett blends a quality-controlled E85, we completely drained and flushed the fuel system in the Valiant and added the Rockett Brand E85.
Simply by running the Rockett Brand E85, our power numbers increased by five horsepower, and our engine had a leaner air/fuel ratio-not a significant amount, but enough to let us know that if we actually tuned with the Rockett E85, we could possibly see a difference of 8-10 horsepower just in the blend of fuel.
Parts Is Not Just Parts
Just converting the engine in your muscle car over to run E85 does take a little more than simply re-jetting your carburetor. We've all heard the horror stories about how E85 can cause damage because prolonged exposure to ethanol may corrode metal and "soften" rubber parts in older engines designed primarily for gasoline. The horror stories are both correct and incorrect. Oil companies are required to add corrosion inhibitors not only to ethanol-blended gasoline but also to other gasoline products (per www.biofuelshub.com). This is because all types of petroleum products have corrosive properties. Changes in humidity and temperature can also affect Ethanol-based fuels more so than petroleum-based fuels. This is because Ethanol-based fuels are prone to absorbing moisture. Ethanol can do some really bad things to some traditional fuel-system materials-like the cork gaskets in some carburetors. Also keep in mind that not all fuel tubing is created equal. Aluminum fuel lines need to be made from anodized tubing. Non-anodized aluminum corrodes when exposed to ethanol.
If you're running a factory, mechanical-style fuel pump, we suggest you change it, as the diaphragm inside might not survive. Even electric fuel pumps are not created equal. We changed ours to a Methanol-compatible fuel pump as our standard aftermarket pump was not designed for this type of fuel. As far as fuel lines, we have gotten mixed reports that standard rubber lines are adequate. Some guys told us that they have had to replace them because of compatibility issues with the E85, and others have been running it for years. Just to be on the safe side, if you're running a large amount of rubber hose (stainless braided and such), it might be a good idea to consult the hose manufacturer about their recommendations.