We see it all the time-Mustangs that aren't safe, nor road-ready, because not enough thought went into their execution. This includes V-8 conversions with wimpy six-cylinder rear axles, 500hp small-blocks with manual drum brakes and 5/16-inch fuel line, mega-horsepower rides with less than adequate steering and suspension systems, and clogged two-row core radiators that cause chronic overheating in new engines. We've also seen high-amp subwoofer sound systems, power windows, video systems, climate control, discharge headlights, and more installed in Mustangs with 45-amp Autolite alternators and Group 24 batteries where owners wonder why their lights are dim. There are also canyon-carving rocket ships with little more than lap belts for safety equipment.
How ready is your Mustang for what you're asking it to do? How safe is it? A boatload of ponies in a Mustang ill-equipped to accommodate all those horses is a good way to get maimed or killed. It also puts others at risk who share the road with you.
How do you get all of your Mustang's components on the same page so they work together like a Swiss watch? What's the best way to plan and execute your dream ride?
Your plan should begin with...
Your plan should begin with suspension and braking because all else is moot in terms of safety and performance without these elements. When you're planning for power, opt for five-leaf mid-eye springs, heavy-duty shackles, urethane/polyurethane bushings, gas shocks, and invisible traction devices such as Shelby traction bars. How you outfit your suspension also depends on how you intend to drive the car. A suspension that's too stiff will jar your teeth. One that's too soft won't provide sufficient handling.
Heavy-duty shackles cannot...
Heavy-duty shackles cannot be seen and provide improved leaf spring stability. Fit the other end with urethane or polyurethane bushings and you're good to go.
Regardless of how much power you build into a classic Mustang, it must have braking and handling that will help you avoid trouble or get you out quickly. You want a Mustang that will take you in the direction it is steered, hold the road, and stop safely. The best accident is the one you avoid.
This Mustang could use a good...
This Mustang could use a good front disc brake package. However, our focus here is springs. Match spring type and rate to the amount of power your engine will make coupled with how you intend to drive the car.
If a stock suspension system...
If a stock suspension system is your objective, shop carefully because not all reproduction parts are created equal. Know the origins of suspension parts before you buy because your safety counts on it. If you're going canyon cutting, plan on a heavy-duty aftermarket suspension system with stiffer springs. Having a stock suspension with a lot of power is like taking a peashooter to a nuclear war. Power, suspension, and brakes must complement one another.
There has never been a better...
There has never been a better time to dial in a classic Mustang suspension system because selection has never been more extensive. Coilover suspension systems, such as this one from Ron Morris Performance, vastly improve handling when you combine them with the right sway bars and tires. It's all pointless without good tire contact patch.
Suspension and brakes must be matched to the amount of power you intend to have along with engine and driveline weight. You can have all the braking and handling in the world, yet come up short because you misjudged engine and driveline weight. Big-blocks, due to size and weight, call for a heavy-duty suspension with stiffer spring rates along with larger brakes. They also call for more cautious driving technique because you can't cheat physics. Braking and suspension choices are also determined by how you intend to drive the car. Road racers require a different approach than drag racers or cruisers.
When you do a bare-shell project...
When you do a bare-shell project car, this is the best time to have a whole car plan. Always opt on the side of safety, not necessarily budget. If you're faced with limited budget, plan on less power in the interest of safety. Build only what you can afford and always with an eye on safety and reliability. All the power in the world is pointless if you're unsafe or can't get power to the pavement.
You can build power into your Mustang's engine compartment. However, without adequate fuel delivery, you're wasting your engine's potential. Your engine must have adequate fuel volume in gallons per hour (GPH) and pressure pounds per square inch (PSI) to perform. This means you need a fuel system that delivers. First and foremost is fuel line size (diameter) followed by adequate fuel pressure. Most classic Mustangs prior to 1969 have 5/16-inch fuel lines designed for six-cylinder engines or small-block V-8s. However, when horsepower rises above 300, your Mustang needs a 3/8-inch line from fuel tank to carburetor. This means sending unit, body fuel lines, all hoses and filters, and fuel pump to carburetor line. If you have a 5/16-inch pathway anywhere in the fuel system, such as the tank-sending unit, you still have 5/16 inch.
Some carburetors, such as the Holley 4150/4160, have fuel filters and fittings at the carb inlet. This has the same effect as a 5/16-inch fuel line. It limits fuel flow and can cause fuel starvation at wide-open throttle.
Carburetor sizing and jetting are also important issues to consider because they have a direct bearing on performance. Popular logic says larger is better, but that's not always true. Too much carburetor along with too much jetting hinders power and pollutes the air. However, we'd rather have too much jetting than too little. A lean mixture at wide-open throttle can harm an engine. We suggest a spark plug reading after a good wide-open throttle run. If the spark plug is snow white, your jetting is too lean. Light tan is the optimum color.
How solid are your Mustang's...
How solid are your Mustang's shock towers? No matter how much power you intend to have, cracked and broken shock towers are dangerous and must be replaced. They also need a good reinforcement package available from Pro Motorsports Engineering.
Disc brakes are an affordable...
Disc brakes are an affordable upgrade you cannot afford to ignore. Braking systems are best chosen based on the kind of driving you're going to do. Stock disc brake packages work quite well for cruising. You want solid braking performance in day-to-day driving. Convert your '65-'66 Mustang to a dual braking system (federally mandated from '67-up) for redundancy and safety.
Fuel capacity also depends on demand, which is determined by fuel consumption at wide-open throttle. Holley tells us your engine is going to need 0.5 pound of fuel per horsepower every hour. A gallon of gasoline weighs six pounds. If your small-block Ford makes 350 hp at wide-open throttle, it's going to mandate 175 pounds of fuel an hour, which is 29 gallons. Use this formula to determine fuel pump needs: 350 hp x 0.5 pound = 175 pounds of fuel; 175 pounds/6 pounds = 29 gallons per hour.
Regardless of how much power...
Regardless of how much power you intend to build into your Mustang, you want handling that will keep you out of trouble. You want a Mustang that will hold the road. Install the fattest sway bar you can get under there in order to minimize body roll. Urethane bushings can be too stiff. One option is polyurethane, which is more flexible. One caution is strut rod bushings. Urethane bushings tend to break strut rods. Go with polyurethane or a fully-articulating strut rod assembly.
Brake pads, like suspension...
Brake pads, like suspension components, should be chosen based on the kind of driving you do most. If you're running a lot of power and plan weekend road racing, you're going to want a high-performance disc brake with heavy-duty friction materials like you get from Baer. High-performance disc brake pads like to get hot. This also means brake noise along with brake dust. If you want quieter brakes, choose an organic or semi-metallic pad, but expect to sacrifice braking effectiveness with an organic pad.
Avoid "larger is better" logic...
Avoid "larger is better" logic when choosing a carburetor. Carburetor sizing depends not only on displacement, but also your engine's performance package (heads, camshaft, intake manifold, compression, and wide-open throttle performance) and how you intend to drive. First question-what do you want the engine to do?
Fuel line sizing is an important...
Fuel line sizing is an important consideration. Imagine aggressively drinking ice tea with a cocktail straw. Remember, fuel line sizing is only as large as its smallest point. If you have 5/16 inch anywhere in the system, you have a 5/16-inch fuel line. Electric fuel pumps do a great job; however, they're unnecessary for the average street Mustang. If you run an electric fuel pump, install an impact kill switch to disable the fuel pump in a collision.
This is courting disaster...
This is courting disaster because not only is it counterproductive to performance, it is also unsafe. Limit your use of rubber fuel line hose to small junctions. Use braided stainless steel hose where you can. Never place a fuel filter over a hot intake or exhaust manifold. Hard line as much of the fuel system as you can.
This is Project Reclaim from...
This is Project Reclaim from Mustangs Plus and The Restomod Shop. Here, they used aluminum 3/8-inch fuel lines for ease of installation and corrosion resistance. Lines should be secured with body clamps or rubber-lined Adel clamps.