Body, Chassis And Drivetrain Science

Our Tech Insider checks out your options for building a street machine.

Words: Larry Shepard

If you are building a street machine, you have many options from rebuilding a muscle car to a full restoration, including various upgrades. This is a pretty large topic so I will limit this article to cars built from 1962 through 1980. But much of the information applies to almost any street car. The main body styles in this category are the B-Body, A-Body and E-Body with much of the same hardware and concerns also applying to the 1976 and newer F-M-J Body cars. Regardless of whether the vehicle is going to be a restoration or a clone, a rebuild or conversion, many of the same concerns apply.

The cars that I have listed average about 35 years old so you can plan on a general hardware rebuild. I’ll start our discussion with chassis items. Remember that most of the steering and suspension parts were discussed in last month’s issue. Keep in mind that cars of this age level will generally require new torsion bar locks and seals P5249609 and clips P4876097 if the torsion bars are removed. It is also a good idea to replace the end-link bushings (sway bar) P4349116 and the strut bushings like P4529184 for the B/E Body cars. Today rear leaf spring bushings for the front and rear spring eyes are sold in sets like P4876196 (A-Body). The rear spring rear-eye bushings are almost always worn-out after 10-30 years of street driving but the front bushing replacement could be considered optional.

One of the key chassis issues for almost all A-Body vehicles is the wheel size and the related wheel attaching bolt circle. The key bolt circle issue is dictated by the basic brake and suspension parts. Almost all of the 1966–1972 A-Body cars used a 4.0" bolt circle. Most of the 1973–1976 A-Body cars used the more common 4.5" bolt circle like all of the B- and E-Body cars. For the non-restoration packages, the trick is to convert the early 1966–1972 A-Body cars to the 4.5" bolt circle. One approach is to use the ball joints lower control arm and knuckles from the newer 1973–1976 A-Bodies. New resto front suspension parts are available from Mancini Racing (1-800-843-2821), which may offer other options. Fabricated parts are offered by Magnum Force (408-559-6633).

Since the manual steering gear is lighter than the power steering gear, many builders want to swap their production power steering package for the manual gear. To accomplish this swap easily you will need the special adapter P4510637 so you don’t have to change the car’s steering column (manual gear is shorter overall). The production manual steering gear had a ratio of 24:1 and can be upgraded to a 20:1 gear P4007612. If you need the basic manual gear housing/assembly, Mancini Racing offers a resto version and Flaming River (800-648-8022) offers a 16:1 assembly. I feel that the 16:1 ratio is too quick for street applications and 440 or HEMI® based engine packages.

The braking system on any given engine/car package is balanced specifically for that engine and body style, including the production wheels and tires. This production setup really only fits the resto approach. Everyone else installs bigger/smaller engines, aluminum engine parts, bigger tires, bigger rear tires, etc., and these packages need the adjustable brake proportioning valve P5249088 to balance braking situations to the specific vehicle package. Production-style wheels like the stock (plain) steel wheels, Magnum 500 wheels, and the Rallye wheels are available from Year One (800-932-7663). They are typically available in 6.0" and up widths in the 14" diameter, and 7.0" and up in the 15" diameter. These production based wheels are only shown for the 4.5" bolt-circle package. Note: aluminum wheels are also hard to find in the 4.0" bolt circle style. Chrome lug nuts (02823848-rt and 02823849-lt) are available for use with these production-based wheels. Also available for these wheels are center caps like P4510579 (1970-style) and trim rings like P3461043 (15" chrome finish). While the plain steel wheels are painted black, the popular rallye wheels tend to be painted argent (special silver)—P4529876.

The 1968 HEMI A-Body package cars came with the battery in the trunk. Many of the 1962–1965 HEMI and Max Wedge package cars also came with the battery-in-trunk. A battery-in-the-trunk kit P4349500AB can be added to almost any car. The basic drivetrain parts were discussed in detail two issues ago, but I should discuss rear axle shafts. The axle shafts hold the key to the wheel’s bolt circle and are the other half of the 4.5" conversion. In the old days, A-Bodies converted to 4.5" bolt circle wheels in the rear by having the production axle shafts re-drilled. Note: The 1968 HEMI A-Body used a B-Body axle (wide) and unique offset wheels. Today more options are available with new, stronger axle shafts available, with the 4.5" BC, from Moser (260-726-6689) or Mancini Racing.

The general topic of “Body” is a very large one and is rarely discussed. Until recently, there weren’t many options. You rebuilt what you had. There are lots of changes in the last few years. Starting with the basic sheet metal, a new steel replacement fender like P5153389 (left), a steel replacement quarter-panel like P5153395 (left), steel hood P5153393 (all three are for the E-Body Challenger) are now available from Mopar®. Left and right floor pan sections and trunk floor pans are available from Year One. The 1968 HEMI A-Body cars were built with fiberglass front fenders. Between Ray Barton Racing Engines (610-693-5700) and MPR (810-798-8998) the Dart and Barracuda A-Body models are pretty well covered for fiberglass parts. Many of the 1962–1964 Max Wedge cars used aluminum front ends and the 1965 HEMI B-Body used thin steel front ends. These packages are very expensive and can’t be replaced, so if you want to drive one on the street consider using fiberglass replacements from WS Racing and Fiberglass Components (440-998-6341). Several Mopar Muscle Cars had fiberglass hoods in limited production. The fiberglass T/A Challenger and AAR ’Cuda hoods are available from Penstar Reproductions (215-957-1622). The ’69 440-6BBL lift-off fiberglass hoods are available from Year One.

While the fiberglass hoods had the scoops built-in (one-piece construction), many of the cars used a separate piece bolted to the hood like the 1967 B-Body HEMI package cars and the 1963 to 1965 Max Wedge and HEMI cars. Reproductions of these hood scoops are available from WS Racing and Year One. Some of the performance models had spoilers and wings added to the basic body and these parts are available from First Place Auto Products (330-493-1420). Many of the production stripe kits for the R/T or Road Runner models along with body decals are available from Graphic Express (352-341-0077) and Performance Car Graphics (850-878-1450). Actual die-cast metal nameplates like 426 HEMI P2998800 are available from Mopar Performance. Exterior body lenses like tail lamps and side-markers are available from Stephens Performance (256-247-1332) and Penstar Reproductions. Basic body moldings are available from Metro Parts (912-383-0172). For the fine details and many body small-parts like the washer bottle, contact Quirey Quality Engineering at 812-963-6097.