When switching your EFI Mustang to carburetion, you'll need a tank pickup from a pre-'86 Mustang. This is a drop-in piece that replaces your EFI pump and pickup assembly with a straight pickup and allows fuel to be drawn up and out of the tank to the feed line. Another option, aside from the factory pickup, is a "sumped" fuel tank or a fuel cell. A sumped tank has an extra well or sump located at the rear/ bottom of the fuel tank, and it keeps a deep pool of fuel waiting at all times. You can buy the tanks with the sump already welded in or you can buy the sump and weld it yourself.
Sumped tanks normally accept aluminum A/N fittings and braided stainless steel fuel lines to carry the fuel to the carburetor. Once you have the fuel flowing from the tank, you can get stock '85 fuel lines or pony up for stainless steel braided hose. The latter are more expensive (usually around $8-$10 per foot, depending on size), but the larger line will provide plenty of fuel for future mods. If using non-stock lines, be sure to route them safely away from the driveshaft, suspension, or bellhousing. The level of power you plan to make will dictate the size of the line. We suggest you contact your engine builder or carburetor manufacturer for fuel-line recommendations.
Once the fuel tank and line are installed, you can mount a fuel pump and filter. You'll need to install a low-pressure fuel filter to prevent grit and debris from getting into the regulator and carburetor. Filters come in all sorts of designs, and the one you'll select will probably come down to what your pocketbook can afford. Some feature reusable/replaceable elements, so look at the long-term cost as well. Often, the manufacturer will recommend a filter that compliments the pump.
An adjustable fuel pressure regulator and gauge are next on the list. Some fuel pumps are designed to operate at certain pressures and others require the fuel pressure to be regulated for optimum performance. Most regulators are made from billet or cast aluminum and can be had for about $50-$100. It's important to set the regulator with the engine running to get a true setting. Pressure will depend on the application, but it should generally be between 7 and 8 psi.
In most cases, the carburetor will not bolt on to your old fuel-injection manifold, so you'll need a new one of those as well. Most aftermarket manifolds are cast aluminum, and there are single-plane and dual-plane designs from which to choose.
Much like the various EFI manifolds, the single- and dual-plane manifolds offer different intake runner lengths and plenum sizes, which change the usable rpm range of the engine. Single-plane manifolds such as Edelbrock's Victor Jr. offer a powerband from 3,500 to 8,000 rpm. This is great for high-rpm horsepower, but low and midrange torque can suffer. So, if you have stock heads and a small cam, a single-plane might not be the best choice.
The choice for most street engines is a dual-plane manifold. The Weiand Stealth or Holley Street Dominator are both dual-plane units and work well in the idle-6,500-rpm range. A dual-plane manifold feeds four cylinders from one side of the manifold and four with the other to improve the signal in the lower rpm range. This helps torque and throttle response.
Carburetors are just as well sorted, with each brand offering different options depending on application. Options like electric choke, manual or vacuum secondaries, and four-corner idle circuits are just some of the things to consider. Driveability-wise, they've come a long way, and while some people don't mind the occasional quirks, EFI still has carbs beat on the street, especially in most blown applications.