They're called bolt-ons because essentially they're simple to install. It's a bit of an automotive misnomer because in many cases there are a few more steps required, such as drilling holes in the right places or correctly wiring anything electrical. For some parts, bolts aren't even needed; we suppose you could call those parts screw-ons or even clip-ons. This month's cover car, a clone of a '67 Shelby GT500, was created primarily with bolt-on parts.
However they install, bolt-ons are designed to improve your vintage Mustang, whether they were originally factory options or accessories, or brand-new restomod-style parts from today's aftermarket manufacturers. Over the next few pages, we're taking a look at some of the more popular bolt-ons for '65-'73 Mustangs to give you some ideas for improving your ride.
With the PerTronix Ignitor and Ignitor II electronic ignition conversion, 30 minutes is all it takes to eliminate the pesky points in vintage factory distributors. With the PerTronix ignition, there's no need for future adjustments. The PerTronix replaces the points with a shutter wheel and ignition module for maintenance-free operation. Both the Ignitor and Ignitor II also provide more voltage for improved performance. Contact: PerTronix, Dept. MM, 440 E. Arrow Highway, San Dimas, CA 91773; 909/599-5955; www.pertronix.com.
You can make a big change in your '65-'66 interior by replacing a standard steering wheel with either a reproduction of the factory Deluxe woodgrain wheel (available from most Mustang parts vendors), a Shelby wood wheel (Branda Shelby and Mustang Parts, Dept. MM, 1434 E. Pleasant Valley Blvd., Altoona, PA 16602; 814/942-1869; www.cobranda.com), or an aftermarket version from Grant (also available from most vendors). Factory-style wheels are a direct replacement, while aftermarket wheels like Grant come with needed adaptors.
Front Disc Brakes
It sounds crazy these days, but the majority of '65-'73 Mustangs came from the factory with drum brakes all around. Of course, front disc brakes were an option, and they were part of certain performance packages, but only a small percentage of Mustangs received them. Today, there are many choices for upgrading to front disc brakes, starting with adding factory-style discs (if you can find the parts) to going all the way up to heavy-duty racing versions. Whichever way you go, make sure you have stainless steel calipers, like those from Stainless Steel Brakes Corporation. SSBC offers complete front disc-brake conversion kits for early Mustangs, including six-cylinder cars, with everything included to upgrade from drums to discs. Contact: Stainless Steel Brakes Corporation, Dept. MM, 11470 Main St., Clarence, NY 14031; 800/448-7722; www.stainlesssteelbrakes.com.
The hot restomod ticket these days is larger wheels and tires, particularly the 17-inch Bullitt versions from '01-'04 GTs or the Magnums found on '03-'04 Mach 1s. National Parts Depot offers an adapter kit for mounting the larger 17-inchers, with their original 245/45R-17 tires, on early Mustangs. Some front fenders may require modification of the wheel-opening radius for clearance. Contact: National Parts Depot, Dept. MM, 900 SW 38th Ave., Ocala, FL 34474; 352/874-7595-9000; www.npdlink.com; California store, 800/235-3445; Michigan store, 800/521-6104; North Carolina store, 800/368-6451.
Brakes have come a long way since 1965-1970. If you step out of your new Mustang GT and jump into your vintage Mustang, you feel like you're shoving your foot through the firewall to get it to stop. Since few vintage Mustangs were equipped with power brakes from the factory, it's been difficult to locate used parts for a proper conversion. But now Master Power offers a bolt-in booster that makes easy work of adding power to your brakes. Better yet, the booster is smaller than the factory piece, which is a big help when installing it on big-block '67-'70 cars. Contact: Master Power Brakes, Dept. MM, 100 Crosslake Park Rd., Mooresville, NC 28117; 888/351-8785; www.mpbrakes.com.
While tubular headers are certainly the way to go for maximum exhaust flow and power, they can be noisy and hot, plus they can cause problems with fitment, burnt spark-plug wires, and blown gaskets. A more factory-style option for 289s and 302s is the factory 289 Hi-Po manifold, as reproduced by California Pony Cars. The Hi-Po manifolds flow better than base 289/302 manifolds, yet they bolt up just like the originals for a factory appearance. California Pony Cars also offers the Hi-Po H-pipes, which connect the Hi-Po exhaust manifolds to factory-style dual exhausts. Contact: California Pony Cars, Dept. MM, 1906 Quaker Ridge Place, Ontario, CA 91761; 888/225-7669; www.calponycars.com.
One of the all-time most popular add-ons for '65-'66 Mustangs is the factory Rally-Pac, a combination tachometer/clock that mounts on the steering column. Originally offered as an option or from the Ford dealer accessory catalog, the Rally-Pac was offered in two styles: low-profile (pictured) for '64 1/2-'65 Mustangs with the Falcon-style speedometer, and high-profile for the five-dial instrumentation in '65 Mustangs with the GT Equipment Group and/or Décor interior and all '66 models. There were three different versions of each style: 6,000-rpm for six-cylinders, 6,000-rpm for V-8s, and 8,000-rpm for the 289 Hi-Po. Original Rally-Pacs are getting harder to find in good condition, and many are the out-of-production reproductions from Dallas Mustang. However, watch for a brand-new reproduction of the Rally-Pac from Scott Drake Mustang Parts. Contact: Scott Drake Mustang Parts, Dept. MM, 3101 Camino Del Sol, Oxnard, CA 93030; 805/988-9992; www.scottdrake.net.
This is the big-daddy of Mustang bolt-ons. Originally an option (albeit rare) on the '66-'67 Shelby GT350, the Paxton supercharger is back as a recently reintroduced kit with the modern Paxton Novi 1200 supercharger. Designed to fit '65-'66 V-8 Mustangs, the Novi 1200 generates 6 to 7 pounds of boost and works with stock four-barrel engines or, better yet, modified engines. With the carburetor housing, supercharger brackets, and all the other components needed to install the system, the Paxton supercharger setup is fairly complicated as a bolt-on. And it's not exactly cheap. But once you feel the boost, it's all worth it. Contact: Paxton Automotive, Dept. MM, 1300 Beacon Place, Oxnard, CA 93033; 888/972-9866; www.paxtonautomotive.com.
At midyear 1969 with the introduction of the Boss 302, Ford began offering a rear spoiler for SportsRoof models, either as a factory option or as an accessory through the dealer parts network. While few '69-'73 Mustangs came with a factory-installed rear spoiler, it's a true bolt-on, so many have been retrofitted over the years. Reproductions are available from most Mustang mail-order vendors, including brand-new repros, for '69-'70 and '71-'73, from National Parts Depot. Contact: National Parts Depot, Dept. MM, 900 SW 38th Ave., Ocala, FL 34474; 352/874-7595-9000; www.npdlink.com; California store, 800/235-3445; Michigan store, 800/521-6104; North Carolina store, 800/368-6451.
Three-Point Shoulder Harness
In the mid-'60s, a single lap belt was state-of-the-art safety. Later, Ford added a shoulder belt, but it was difficult to use so most never bothered. Today, you can upgrade to a true three-point seatbelt system from Custom Accessories. Although they've been on the market for a while, the newest design reduces, and in some cases eliminates, the need to drill holes. You can opt for front seats only or go for a complete set of front and rear. Contact: Custom Accessories, Dept. MM, 1030 W. Williamson Way, Fullerton, CA 92833; 800/560-2358; www.customaccessoriesmfg.com.
Just a few months ago, this wasn't even an option for '67-'68 Mustang coupes and fastbacks because original overhead consoles were so hard to find. But now that Scott Drake Mustang Parts has reproduced the entire assembly, it's a great addition to '67-'68s. The overhead console adds style to the interior, plus it provides a couple of map lights. We highlighted the installation in our July '04 issue. Contact: Scott Drake Mustang Parts, Dept. MM, 3101 Camino Del Sol, Oxnard, CA 93030; 805/988-9992; www.scottdrake.com.
A good-looking option with the Exterior Décor Group on '67 Mustangs was the aluminum rear-panel grille. Originals are difficult to find in good shape, but now you can get reproduction grilles from California Mustang. Sold in pairs, one panel for each side, the grilles are available to fit '67-'68 hardtops, convertibles, and fastbacks. Drilling may be required. Contact: California Mustang, Dept. MM, 19400 San Jose Ave., City of Industry, CA 91748; 800/775-0101; www.californiamustang.com.
Sanden A/C Compressor
If your vintage Mustang is air conditioned and it's still running the ancient York compressor with the older and more expensive R12 refrigerant, you can make a big step up by switching to a modern Sanden compressor, along with 134a refrigerant, from Classic Auto Air. Not only is the 134a refrigerant more wallet-friendly, the Sanden compressor will make a big difference in your Mustang. In addition to its light weight and neater appearance, the Sanden compressor requires less horsepower to operate (it's like gaining 10 hp, says CAA's Al Sedita) and the seven-cylinder design is much smoother and quieter than the two-cylinder York. For the compressor swap, you'll need the Sanden Compressor Conversion Kit, which consists of the Sanden compressor, adaptor bracket, new filter-dryer, and new hoses. Contact: Classic Auto Air, Dept. MM, 2020 W. Kennedy Blvd., Tampa, FL 33606; 813/251-2356; www.classicautoair.com.
No one will argue that the vintage Mustang speaker system-a single 6x9 in the instrument panel-wasn't even state-of-the-art for '65-'66, much less today. One way to boost the sound in your vintage Mustang is to install Custom Autosound's kick-panel speakers. Perfect replacements for '65-'66 standard kick panels, the CA panels incorporate 80-watt coaxial (two-way) speakers to greatly enhance sound quality, especially when used in conjunction with Custom Autosound's AM/FM/CD head units. Contact: Custom Autosound, Dept. MM, 1030 W. Williamson Ave., Fullerton, CA 92833; 800/888-8637; www.custom-autosound.com.
Rack-and pinion steering is now available for early Mustangs as a true bolt-in, with no cutting, welding, or drilling required. Designed to work with the original '65-'69 spindles or with '70 Mustang or Granada disc brake upgrades, Flaming River's new rack-and-pinion setup includes a quick 16:1 ratio, making it feel more like power steering without the hassle of plumbing a complete power-steering system. Look for more on the rack-and-pinion installation elsewhere in this issue. Contact: Flaming River Industries, Dept. MM, 800 Poertner Dr., Berea, OH 44017; 800/648-8022; www.flamingriver.com.
For this time-honored modification, there are hundreds of choices, from cast-iron four-barrel upgrades to vintage aluminum Shelby/Cobra units, to the many current offerings from companies such as Edelbrock, Weiand, Holley, and Offenhauser. On top of that, you've got multiple carburetion and Webers. For an everyday street engine, look for a dual-plane four-barrel manifold, which provides better torque for everyday driving. Single-planes produce more horsepower, but at higher rpm, which is more suitable for racing.
If you're searching for impressive underhood looks and more power, check out the tri-power setup from Pony Carburetors. Unlike the original Ford tri-power, which used a trio of Holley two-barrel carbs, the Pony Carburetors version for the small-block Ford engine utilizes three Autolite 2100 two-barrels and Pony Carburetor's own aluminum intake. Around town, the engine purrs on the center carb. But when you need more juice, the outbound carbs pop open another four barrels of fun. Contact: Pony Carburetors, Dept. MM, 112 Westgate St., Las Cruces, NM 88005; 505/526-4949; www.ponycarburetors.com.
As we pointed out in last month's issue, upgrading to a clutch fan, available from most Mustang parts vendors, will certainly enhance your Mustang's cooling system and save power at the same time. Sold as two separate pieces-clutch and fan-that must be bolted together, the clutch locks in at low speeds to draw air through the radiator but freewheels at higher rpm to conserve power. In most cases, it's a direct bolt-on replacement for the four-blade fan that came on most early Mustangs.
It would be impossible to put together a performance bolt-on article and not mention Holley carburetors. Since 1957, when Holley introduced the 4150 four-barrel on the '57 Thunderbird, it has been producing carburetors for both aftermarket and OEM. Today, Holley carbs are a favorite for Mustang performance. They're easy to install and tune, plus they're available in a variety of sizes, secondary configurations, and models. Contact: Holley Performance Products, Dept. MM, 1801 Russellville Rd., Bowling Green KY 42101; 270/781-9741; www.holley.com.
GT Fog Lights
Nearly every Mustang parts vendor offers the reproduction bars, brackets, wiring harnesses, switches, and bulbs to install GT fog lights in '65-'68 Mustang grilles. They make a sporty addition to the early Mustangs, and provide more visibility for both the driver and other traffic. Check with your favorite parts vendor for more details.
When it comes to performance, less weight is a good thing. With an aluminum driveshaft from Mustangs Plus, you can send more horsepower to your rear wheels because the lighter shaft requires less engine power to turn. Contact: Mustangs Plus, Dept. MM, 2353 N. Wilson Way, Stockton, CA 95205; 800/999-4289; www.mustangsplus.com.
The early Mustang's leaf-spring rear suspension has never won any awards as a top-performer for hard launching. One reason is, the springs have a tendency to wind up or twist under hard acceleration, which results in wheelhop. Carroll Shelby recognized the problem early and added Traction Master under-ride traction bars to his GT350s. Those same traction bars are available today to solidly locate the axle to prevent rear-axle windup. The Traction Master bars install using the rear-axle U-bolts, and their front mounting plates must be welded to the framerails. Contact: Traction Master, Dept. MM, 2917 W. Olympic Blvd., Los Angeles, CA 90006; 213/382-1131; www.tractionmaster.com.
For optimum handling, you'll need a set of performance shocks, like the Gas-o-matics from KYB. They provide just the right amount of stiffness for a vintage street Mustang, allowing for a feeling of confident control without excessive harshness. The KYBs, offered by most Mustang vendors, offer multistage valve compression to enable the shocks to adjust to driving conditions automatically. Check with your favorite vendor for more details.
One of the more stylish options-and available over the counter-for '69-'70 Mustang fastbacks was the rear-window louver. In addition to the good-looking European styling, the louvers also covered the fastback's huge rear window to keep direct sunlight from baking the interior. Now available as a top-quality reproduction from National Parts Depot, the louvers install with Rivnut fasteners after drilling holes in the roof and below the rear window. Hinges, latches, and Rivnuts are included. Contact: National Parts Depot, Dept. MM, 900 SW 38th Ave., Ocala, FL 34474; 352/874-7595-9000; www.npdlink.com; California store, 800/235-3445; Michigan store, 800/521-6104; North Carolina store, 800/368-6451.
Carroll Shelby figured out this trick for his GT350s when he discovered these beefier shock-tower-to-cowl braces on Mustangs destined for export out of the United States. In most cases, they simply replace the flimsy braces on '65-'70 Mustangs to stabilize the front end for better handling. On some cars, however, it may be necessary to spread the shock towers so the brace will fit. Export braces, either black or chrome, are available from most Mustang parts vendors.
Rear Disc Brakes
If you already have front disc brakes or you want to convert to disc brakes all around, Stainless Steel Brakes has the kit for that too. SSBC's rear disc brake kit for early Mustangs comes with rotors, four-piston calipers, brackets, brake pads, and splash shields-everything you need to convert to rear-wheel disc brakes, which will bring your Mustang's stopping power up to modern standards.
There are many choices for upgrading your side mirrors. Since most Mustangs came with a single driver-side mirror, you can always add another mirror on the passenger side for improved rear visibility. Other upgrades include the switch to a deluxe mirror with remote control, Shelby "bullet" mirrors, or dual racing mirrors, like those found on Mach 1s and Bosses, for '69-'73 Mustangs. Check with your favorite Mustang parts vendor.
Heads Above The Rest
For a real performance jolt, bolt on a set of performance heads in combination with a free-breathing intake and carburetor. Thanks to the late-model 5.0 craze, we now have plenty of choices for Windsor small-blocks, from the factory cast-iron offerings to the latest aluminum versions from Edelbrock, Ford Racing, Holley, World Products, and others. FE engines also benefit from aluminum heads, which are offered by Edelbrock and Shelby Automotive.
With Hot Rod Air's '65-'66 Mustang radiator and electric fan assembly, you get two bolt-ons in one. The package comes with everything you need to upgrade to a three-row radiator and electric fan, which comes with its own shroud and adjustable thermostat. The radiator provides additional coolant capacity, while the electric fan cools only when needed while conserving engine power at the same time. Contact: Hot Rod Air, Dept. MM, 9330 Corporate Dr., Suite 303, Selma, TX 78154; 877/693-3200; www.hotrodair.com.
An affordable and easy-to-install option for six-cylinder Mustangs is the dual-exhaust header from Jack Clifford Performance. The dual outlets help simplify the installation of dual exhausts. Ceramic-coated, the Clifford header features heavy-duty flanges and thick exhaust gaskets to ensure quiet operation. Contact: Jack Clifford Performance, Dept. MM, 32840-B Wolf Store Rd., Temecula, CA 92592; 909/303-2333; www.cliffordperformance.com.
Ever since Eleanor arrived on the scene in the remake of the Gone In 60 Seconds, the movie car's Cobra-style wheels have become a popular item for vintage Mustangs, especially '67-'68 fastbacks. The 17x8-inch wheels from PS Engineering add a meaty, racy look to early Mustang styling. Contact: PS Engineering, Dept. MM, 2665 Skypark Dr. No. 102, Torrance, CA 90505; 310/534-4477.
Thanks to Mustang Project's new LED sequential kit, it's easy to convert the '65-'69 Mustang's tri-panel taillights to sequential operation. Mustang Project's kit includes only three parts: a pair of LED modules and a flasher unit. The modules simply replace the OEM-style bulbs, and the flasher plugs into the original flasher wires in the main wiring harness behind the instrument panel. Attach the black wire to a convenient ground location, and you're on the road with flashy sequential taillights. About 10 minutes and a screwdriver is all you need. Contact: Mustang Project, Dept. MM, 912 Cashew Lane, Cedar Park, TX 78613; e-mail to firstname.lastname@example.org; www.mustangproject.com.
R-Model Front Valance
You can make a complete transformation in your '65-'66 Mustang's appearance with a Shelby R-Model front valance from Cobra Automotive. Designed for an exact fit with no need for additional bodywork, the Cobra Automotive R-Model apron includes the correct rear flanges for functional brake-cooling hoses. Cobra Automotive now has R-Model-style front aprons for '67-'68 Mustangs. Contact: Cobra Automotive, Dept. MM, 37 Warehouse Point Rd., Wallingford, CT 06492; 203/284-3863; www.cobraautomotive.com.
For '65-'68 Mustang coupe owners who want to add more punch to their music, Custom Autosound offers a Back Seat Driver with a pair of 8-inch subwoofers and a 120-watt amplifier. Made from high-density pressboard and covered with black cloth for a finished appearance, the Back Seat Driver replaces the flimsy cardboard behind the rear seatback. "Mustang Sally" never sounded so good. Contact: Custom Autosound, Dept. MM, 1030 W. Williamson Ave., Fullerton, CA 92833; 800/888-8637; www.custom-autosound.com.
The choices are endless: Flowmaster, MagnaFlow, Borla, Flowtech, Hooker, Dynomax, and others. While increased horsepower is certainly a goal when switching to performance mufflers, we're also interested in the exhaust tone. Sometimes, when you hear a Mustang with the sound you like, you just have to stop the owner and ask what he's running. Of course, exhaust tone is subjective; some like it loud and some like it mellow. Do your research before bolting or welding them in.
The front chin spoiler practically became mandatory equipment on performance Mustangs after it debuted on the '69 Boss 302. It was offered as an option through 1973, and you can still get it from Mustang mail-order vendors. Just drill the holes in your existing valance and screw the spoiler on for that musclecar look.
Bigger Sway Bar
A larger front sway bar from Mustangs Plus is a quick and easy way to improve handing. The Grab-a-Trak 1-inch sway bar is a direct replacement for the factory front sway bar. It comes with new links and brackets for a hassle-free installation. While you're at it, add a Mustangs Plus Grab-a-Trak rear sway bar. Contact: Mustangs Plus, Dept. MM, 2353 N. Wilson Way, Stockton, CA 95205; 800/999-4289; www.mustangsplus.com.
Free-Flow Air Filter
This one is so simple that it almost defies inclusion in a bolt-on article. Most Mustangs came with a closed air cleaner, which draws air from the constrictive snorkel. You can replace it and still maintain a factory look with a Hi-Po open-element filter assembly, available from all Mustang parts vendors. Better yet, when you receive the air cleaner, install a K&N Filtercharger, a washable and reusable filter that flows more air than conventional paper filters. Contact: K&N Engineering, Dept. MM, P.O. Box 1329, Riverside, CA 92502; 800/760-5319; www.knfilters.com.
Retro accessories are always cool, especially when they look good and serve a safety purpose at the same time. During the mid-'60s, Ford offered the Rotunda headrests, designed for head and neck safety in a collision, for '65-'66 Mustangs. Now SafeCode has reproduced the Rotunda headrests, right down to the brackets that bolt to the rear of the seat. Contact: SafeCode, Dept. MM, 912 Cashew Lane, Cedar Park, TX 78613; 512/260-6786; www.mustangproject.com.
Want great looks, lighter weight, and a cooler engine compartment with one easy bolt-on? Try a fiberglass hood with a cowl scoop from Maier Racing. Granted, you'll need to have the hood painted to match your '65-'70 Mustang, but the benefits are worth the effort. Hood springs aren't used, so you'll need a prop rod. Maier also offers a number of other early Mustang hood styles, including Shelby. Contact: Maier Racing, Dept. MM, 22215 Meekland Ave., Hayward, CA 94541; 510/581-7600; www.maierracing.com.
Aluminum Water Pump
When your old water pump finally gives up, replace it with an aluminum water pump from Edelbrock that offers better flow, optimum pressure, and equal distribution to both sides of the block. Edelbrock aluminum water pumps are available for small-block and 429 Mustang engines. Contact: Edelbrock, Dept. MM, 2700 California St., Torrance, CA 90503; 310/781-2222; www.edelbrock.com.
A great way to dress up the exterior of a '69-'70 Mustang is to add a Mach 1 scoop to the hood. Just drill six holes and you're ready to bolt it on. You can even make it functional with a larger opening and a factory-style ram-air air cleaner. The scoops are available at a reasonable price from all Mustang mail-order parts vendors.
When it's time to replace your alternator, don't run down to your local auto parts store to get a rebuilt unit. You can order an exact replacement alternator, right down to the markings on the housing, from AMK Products (Dept. MM, 800 Airport Rd., Winchester, VA 22602; 540/662-7820; www.amkproducts.com). On the outside, AMK's alternators are exact in detail, but they're completely remanufactured inside with new components. If you're running a lot of power-consuming accessories, such as a high-powered stereo, check out the more powerful alternators from Powermaster (Dept. MM, 7501 Strawberry Plains Pike, Knoxville, TN 37924; 865/688-5953; www.powermastermotorsports.com). They offer higher amperage, from 90 to 120.
Crane Cams' aluminum roller rocker arms not only reduce friction with needle-bearing fulcrums and roller tips, they can also add more lift to your camshaft if you bolt-on 1.7 versions instead of the factory 1.6 ratio. Contact: Crane Cams, Dept. MM, 530 Fentress Blvd., Daytona Beach, FL 32114; 386/252-1151; www.cranecams.com.
For attractive underhood looks, bolt on a pair of aluminum Cobra valve covers, available from all major Mustang parts vendors. They're available for small-blocks and big-blocks in a variety of styles, including natural aluminum and black crinkle.
You don't typically think about seats as bolt-ons, but since they install in vintage Mustangs with just four bolts per seat, we suppose they really do fit the bolt-on theme. M-Detail now offers a Pony Interior-style high-back that incorporates all the comforts of a modern bucket seat, such as adjustable headrests, seatback, and knee bolsters. Better support for long rides is another plus. You can even get leather. Contact M-Detail at 909/686-3929.
Mustang interiors look their best with a floor console mounted between the bucket seats. An option in the '60s, many Mustangs didn't come with the console, so it's a great addition. You may be able to find an original console for your '65-'73 Mustang at a swap meet and refurbish it with many of the reproduction parts available today. For '65-'66 owners, you can practically build a brand-new console from reproduction parts, starting with the repro console housing offered by major Mustang vendors.
Shelby had some great ideas for his Shelby Mustangs, and you can still take advantage of them. One is the gauge pod that positioned a tachometer and an oil-pressure gauge on the center of the instrument panel in '65 GT350s. A reproduction of the gauge pod is still available today from Mustang mail-order companies, providing a great spot for adding an aftermarket tachometer and a smaller gauge.
With Jack Clifford Performance's carburetor adaptor, owners of 170ci, 200ci, and 250ci Mustang six-cylinder engines can upgrade from one-barrel to two-barrel carburetion, using either an Autolite or Holley carburetor. It's an easy way to add more horsepower to an inline six. Contact: Jack Clifford Performance, Dept. MM, 32840-B Wolf Store Rd., Temecula, CA 92592; 909/303-2333; www.cliffordperformance.com.
Headers rank as one of the best all-time bolt-on modifications for '65-'73 Mustangs. There are tons of choices out there, from Shelby-style tri-Ys to equal-length headers from companies such as Hooker, Hedman, and JBA. Most small-block headers practically fall into place, while big-blocks require more patience due to the tight fit. In all cases, you'll need to have a muffler shop fabricate H-pipes to the mufflers.