Q: I’m getting ready to plumb my ’33 Ford with new fuel lines. What type of line should I be using?

A: It’s no secret, the formulation of pump gas has changed dramatically over the years. Your next fill up is likely to contain a blend of gasoline and ethyl alcohol (ethanol), plus an ever-changing recipe of chemical additives.

While they’re suitable for use in most modern vehicles, blended fuels can permeate and break down the rubber fuel lines found in many classic cars and trucks. When it’s time to re-plumb your fuel system, you should choose a hose that can handle modern fuel blends.

For stock replacement applications, check out fuel injection hose from Continental or Dayco. Both feature a fluoroelastomer tube-liner for low fuel-permeation and high chemical-resistance, so they’re perfect for use with ethanol-blended fuel. Plus, they’re rated up to 100 psi of working pressure.

While braided AN hose is a great choice for performance and show car applications, some AN hose is unsuitable for use with blended fuel. Summit Racing PTFE hose and Fragola Performance Systems Series 6000 both offer high resistance to fuel permeation, and are compatible with every type of current automotive fuel on the market. AN hose that’s incompatible with pump gas can allow fuel vapor to escape, producing the aroma of fuel around your vehicle, and it will have a shorter service-life expectancy.

This is another in a series of weekly Q&A Mailbag sessions with Summit Racing‘s tech department, in which there are hundreds more. Click here to see them all.

Author: Dave Matthews

Dave Matthews was a mechanic for the U.S. Army, a Ford dealership, and served for many years as a fleet mechanic for construction companies. Now a technical content producer at Summit Racing, Dave has spent decades working on everything from military vehicles to high performance race machines.