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November, 2011 - Mark J. McCourt
It's no stretch to say that, of the pre-II Mustangs, it's the last ones that are least remembered. After all, today's regular retro-styled Mustangs ape the 1965-1968 Fastbacks, while the exciting 2011 Boss 302 recalls the 1969-1970 models. So where's the love for the 1971-1973s?
These large, smooth cars were equal parts grand tourer and street brawler, and following Mustang tradition, they could be optioned from mild to wild, with six- or eight-cylinder power and plenty of luxury trimmings. They may not share earlier models' build-from-a-catalog parts availability, and their road-hugging style may not be to everyone's taste, but those who consider the 1971-1973 Mustang will find that they can get into a bona fide classic pony car for surprisingly little cash.
Changing tastes and a changing market were among the factors leading to the Mustang's falling sales figures, which had gone from a 1966 high of 607,568 to 190,727 in 1970, but Ford did their best to reverse the trend with the new hardtop coupe, fastback Sportsroof and convertible designs introduced for 1971. Built on a 109-inch wheelbase, these 190-inch-long cars were fractionally larger than their predecessors in every dimension. Their long, broad hoods, truncated rears and thick-waisted styling blended classic Mustang elements with Italian GT cues. Sportsroofs had wide C-pillars and nearly vertical rooflines, while hardtop coupes featured a tunneled rear window framed by flying buttresses that extended the roofline nearly to the trailing edge of the trunk. The convertible's new soft-top design increased usable rear seat room. All new models shared a twin-cove dashboard design with deeply tunneled instruments and a prominent center stack.
Base Mustang coupes ($2,911 with an inline-six, $3,006 with a 302-cu.in. V-8), Sportsroofs ($2,973/$3,068) and convertibles ($3,227/$3,322) were equipped with reclining vinyl-covered bucket seats as standard equipment, as well as color-keyed nylon carpeting, DirectAire fresh-air ventilation, courtesy lights and concealed windshield wipers. Luxurious Grandé coupes ($3,117/$3,212) added high-back bucket seats trimmed in cloth, a deluxe instrument panel, upgraded interior trim, a vinyl roof and rocker and wheel arch trim. Sporty Mach 1s ($3,268, V-8 only) added a color-keyed spoiler, mirrors and moldings, a special grille with integrated Sportlamps and E70 x 14 tires. The top Mustang in 1971 was the $4,124 Boss 351, which used functional NASA-style hood scoops, black or Argent tape stripes and hood paint, dual exhausts, power front disc brakes, a competition suspension and a Traction-Lok differential. A new variable-ratio (15.7:1) power steering system was standard on the Boss 351, while a conventional fixed-ratio system could be had on other Mustangs.
Changes for 1972 and 1973 were minimal. A color-keyed front bumper and fresh nameplate script badges highlighted 1972's coupe ($2,729/$2,816), Sportsroof ($2,786/$2,873), convertible ($3,015/$3,101), Grandé ($2,912/$3,002) and Mach 1 ($3,053). A new décor package could make a hardtop or convertible look like a Mach 1. The Boss 351 was discontinued, leaving the High Output 351-inch V-8-equipped Mach 1 as the top performer. Reshaped front fenders, a flexible extruded urethane front bumper and a new crosshatch-textured grille with framed headlamps and vertical parking lamps set the 1973 Mustangs apart. The convertible Mustang sold very well in 1973, but it would be Ford's last soft-top until its Fox-platform descendant appeared ten years later.
Although the new models garnered interest, sales figures continued to soften, with 149,678 units sold in 1971 and 125,093 sold in 1972. Ford dealers' outlooks brightened a bit in 1973, when 134,867 pony cars left their lots. While these numbers can't touch those of the first generation cars, nearly 410,000 were sold, and many of these are still roadworthy today, so it's fun and easy to get into a late-early Mustang.
The basic engine in most Mustangs was an OHV 250-cu.in. inline-six. Also used in Mavericks, it had a 3.68 x 3.91-inch bore and stroke, 9.0-compression and breathed through a 1-bbl. Motorcraft carburetor to make a gross-rated 145hp at 4,000 RPM and 232-lbs.ft. of torque at 1,600 RPM. The basic V-8 upgrade was a 302-cu.in. engine (standard in the Mach 1), which had a 4.00 x 3.00-inch bore and stroke and 9.0 compression. With a 2-bbl. Motorcraft carburetor, it produced 210hp at 4,600 RPM and 296-lbs.ft. of torque at 2,600 RPM. Upgrading to the 2-bbl.-Motorcraft carbureted 351-cu.in. "Cleveland" V-8, with its 9.0-compression and 4.0 x 3.50-inch bore and stroke, netted 240hp at 4,600 RPM and 350-lbs.ft. of torque at 2,600 RPM. A premium-fueled Holley 4-bbl. carburetor and a 10.7:1 compression ratio brought its horsepower to 285 at 5,400 RPM and torque to 370 at 3,400 RPM. The new 351 Cobra Jet used 8.6-compression and ran on regular octane gas, offering 280hp at 5,800 RPM and 370-lbs.ft. of torque at 3,400 RPM.
The Boss 351's engine was a modified 351-inch V-8 that used shot-peened and magnafluxed steel connecting rods (vs. forged steel), forged aluminum pop-up pistons (vs. cast aluminum flat-top), a 4-bbl. Autolite model 4300-D carburetor with a spread bore pattern (vs. an Autolite 4300-A with a standard bolt pattern), mechanical camshaft and tappets (vs. hydraulic) and a nodular iron flywheel (vs. cast iron). With its standard ram-air intake and 11.7-compression, the Boss 351 engine made 330hp at 5,400 RPM and 370-lbs.ft. of torque at 4,000 RPM. Car and Driver tested it to 60 MPH in 5.8 seconds, and running the quarter-mile in 14.1 at 100.6 MPH. There were two further optional V-8s; the wedge-head 429 Cobra Jet and 429 Super Cobra Jet both displaced 429-cu.in. via a 4.36 x 3.59-inch bore and stroke, breathing through Holley 4-bbl. carburetors to make 370hp at 5,400 RPM or 375hp at 5,600 RPM, and an identical 450-lbs.ft. of torque at 3,400 RPM.
The hottest engine for 1972 was the 351 High Output, which offered a net-rated 275hp at 6,000 RPM and 286-lbs.ft. of torque at 3,800 RPM. Increasing smog controls and the switch to net ratings lowered power ratings across the board: The 250-cu.in. inline-six slipped to 8.0-compression and 98hp (1972) or 88hp (1973); the 302-cu.in. V-8 to 8.5-compression and 140hp (1972) or 135hp (1973); the 2-bbl., 351-cu.in. V-8 to 8.3-compression and 164hp (1972) or 156hp (1973); the 4-bbl. 351 to 8.6-compression and 248hp (1972) or 154hp (1973), and the 351 Cobra Jet slipped to 8.6-compression and 266hp. All of the parts that these well-built engines require are available either over the local parts-store counter or from Mustang specialists, and anyone with a good set of tools, a shop manual, and some time and energy can solve almost any Mustang mechanical issue.
A console-mounted three-speed manual transmission was standard with the 250-cu.in. I-6, the 302-cu.in. V-8 and the 351-cu.in. V-8. A three-speed Select-Shift Cruise-O-Matic automatic transmission, known internally as the C4, was optional. A heavy-duty C6 automatic could be had with 4-bbl.-carbureted 351Cs and 429s. Truly sporting drivers of 4-bbl.-carbureted 351 and 429-cu.in. V-8-powered cars opted for a four-speed manual "top-loader" transmission, in wide- or close-ratio form. In first through fourth gears, the wide ratios were 2.78:1, 1.93:1, 1.36:1 and 1.00:1, while the close ratios were 2.32:1, 1.69:1, 1.29:1 and 1.00:1. Whether automatics or manuals, Mustang transmissions are highly regarded as bulletproof, and because they were common with other Fords, parts are plentiful.
These cars shared a semi-floating hypoid rear axle. Garden-variety six- and eight-cylinder Mustangs used an eight-inch rear end, while high-performance V-8 cars came with a nine-inch rear end. A vast number of final drive ratios were available both in open and locking forms; conventional open ratios included 2.79:1, 3.25:1, 3.40:1 and 3.50:1; and ratios available with the limited-slip Traction Lok or Detroit Locker rear end included 3.00:1, 3.25:1, 3.50:1, 3.91:1 and 4.11:1. Eight-inch rears can't handle big power, so installing a sturdy nine-inch rear end is a smart bet for modified cars.
SUSPENSION AND BRAKES
The 1971-'73 Mustangs were built with ordinary, yet tunable, underpinnings. Their independent front suspensions consisted of angle-poised ball joints, coil springs, tube shocks and a link-type anti-roll bar. The live-axle rear suspension used variable-rate asymmetrical leaf springs and tube shocks that were diagonally mounted, on cars with 351-cu.in. or larger engines. An available competition suspension offered a rear anti-roll bar (½-inch on Mach 1, 5/8-inch on Boss 351), heavy-duty front springs and shocks. Staggered rear drag racing shocks were also fitted to 351--4-bbl. V-8--and greater-powered cars. Substituting modern suspension components can upgrade these cars' ride and handling measurably.
All Mustangs shared a dual hydraulic system, and four-wheel manual drum brakes were standard on most models. Base cars used 10 x 1¾-inch rear drums, while performance models used 10 x 2-inch versions shared with Ford Fairlanes, Torinos and Mercury Cougars. Optional on mild Mustangs and required with high-po cars was a power front disc brake setup. The four-wheel drum systems offered 154.0 or 173.3 square inches of lining, while the disc/drum setup gave 231.0 square inches of swept area. As with Mustang engine components, brake parts are inexpensive and easy to locate, and disc brake conversions are simple and effective.
Unless a Mustang has lived in a desert climate all its life, it will more than likely exhibit some rust. Two noted problem spots in 1971-1973 cars are the cowl area under the windshield, and the front frame rails. Reproduction metal for these areas isn't being made, and replacements have to either be cut from donor cars or be fabricated from scratch. Rust in the floor pan, rear frame rails, trunk floor or rocker panels is less serious, as patch and full repair panels are available from many sources.
Because these late cars will cost as much--or more, in the case of fewer reproduction panels--to repair as will earlier, more valuable models, it pays to find the most solid example that you can, even if it costs more: You'll save money in the long run.
The Mustang's new interior featured high-back seats covered in durable vinyl, with carpeting on the floor and lower door panels. The standard floor shift mini console could be replaced with a full-length version, and center console-mounted oil, temperature and alternator gauges were included on performance models and optional on others. Select-Aire air conditioning, Tilt-Away steering wheels, AM/8-track stereos and power windows were appealing options. Sportsroofs often require new interior materials due to sun damage from their large, nearly horizontal rear windows, but replacement upholstery, door panels, carpeting and more are carried by numerous specialists.
Production Mustang I-6/V-8*
Coupe -- 12,181/53,521
Sportsroof -- 1,296/22,659
Convertible -- 679/5,442
Grandé -- 568/16,838
Mach 1 (Sportsroof) -- 36,498
Boss 351 (Sportsroof) -- 1,806
Coupe -- 8,137/49,213
Sportsroof -- 614/15,008
Convertible -- 565/5,836
Grandé -- 465/17,580
Mach 1 (Sportsroof) -- 27,675
Coupe -- 6,273/45,207
Sportsroof -- 415/10,406
Convertible -- 723/11,130
Grandé -- 516/24,758
Mach 1 (Sportsroof) -- 35,439
* Mustang production data copyrighted by the Ford Motor Company and Marti Auto Works.
Fender, front -- $335
Floor pans (full-length, per side) -- $90
Taillamp panel -- $113
Rear disc brake conversion kit -- $825
Convertible top boot -- $80
Thermostat -- $12
Grille, 1973 Mach 1 -- $140
Bumper, rear -- $100
Stripe kit, 1971-72 Mach 1 -- $90
Gas tank -- $130
Exhaust system, dual -- $225
Upholstery set, 1971 Grandé -- $360
Radio bezel -- $70
Timing chain set, 351 Cleveland -- $30
Carpet set, standard 1971-73 -- $128
Battery tray -- $19
Front windshield molding -- $140
Wheels (Magnum 500 15 x 7, set of 4) -- $675
WHAT TO PAY
Low Average High
1971 Convertible $7,500 $14,000 $33,000
Sportsroof $4,000 $9,000 $25,500
Coupe $3,500 $8,000 $22,500
Grandé $4,500 $10,500 $29,000
Mach 1 $13,500 $25,000 $60,000
Boss 351 $22,500 $44,000 $71,000
1972 Convertible $7,500 $15,500 $33,500
Sportsroof $4,000 $10,500 $23,500
Coupe $4,000 $9,500 $22,000
Grandé $4,500 $10,000 $23,500
Mach 1 $9,000 $16,000 $33,500
1973 Convertible $9,000 $16,000 $34,500
Sportsroof $4,500 $11,500 $27,500
Coupe $3,500 $8,000 $21,000
Grandé $5,500 $10,500 $25,000
Mach 1 $8,500 $16,500 $39,000
Auto City Classic, Inc 800-828-2212 www.autocityclassic.com
Auto Krafters, Inc 800-228-7346 www.autokrafters.com
Tony D. Branda 800-458-3477 www.cobranda.com
Dallas Mustang 800-687-8264 www.dallasmustang.com
Scott Drake 800-999-0289 www.drakeautomotivegroup.com
Glazier/Nolan Mustang Barn 800-523-6708 www.mustangbarn.com
Bill Herndon's Pony Warehouse 919-435-0396 www.ponywarehouse.net
Larry's Thunderbird and Mustang Parts 800-854-0393 www.larrystbird.com
Marti Auto Works 623-935-2558 www.martiauto.com
Mustangs and More 800-356-6573 www.mustangs-more.com
Mustangs Unlimited 888-229-2929 www.mustangsunlimited.com
National Parts Depot 800-874-7595 www.nationalpartsdepot.com
Obsolete and Classic Auto Parts 800-654-3247 www.classicautoparts.com
Ohio Mustang Supply 440-949-2556 www.ohiomustang.com
California Pony Cars 888-225-7669 www.calponycars.com
New England Mustang 800-242-2314 www.ponypartsplus.com
Mustang Depot of Las Vegas 702-262-0011 www.mustangdepot.com
K.A.R. Auto Group, Inc. 800-341-5949 www.karmustang.com
Mustang Club of America www.mustang.org 850-438-0626 Dues: $50/year Membership: 9,000
Mustang Owners Club International 505-296-2554 Dues: $15/year Membership: 500
This article originally appeared in the November, 2011 issue of Hemmings Motor News.