Installing a B&M Shifter in Your A-Body Mopar

Upgrading to a B&M shifter is one of the most effective ways to improve shift feel and power delivery in your A-body Mopar (Dart, Duster, Valiant, Barracuda, etc.). Unlike a sloppy factory column shifter or a poorly maintained floor unit, a B&M shifter gives you crisp, positive engagement with each gear change. This guide walks you through the full installation process and then goes beyond basic fitment to show you how to optimize your entire drivetrain for maximum power delivery. Whether you are building a street cruiser or a weekend drag car, the steps below will help you get the most out of your B&M shifter.

Tools and Materials You Will Need

Before you begin, gather everything you need. Having the right tools on hand saves trips to the hardware store and prevents frustration. Below is an expanded list beyond the basic shifter kit contents.

  • B&M shifter kit – typically includes the shifter body, mounting bracket, shift cable, hardware, and instruction sheet. Important: verify the kit is designed for your A-body chassis and transmission type (e.g., 727 TorqueFlite or 904).
  • Socket and ratchet set – standard and metric sizes; 3/8-inch drive is usually sufficient.
  • Combination wrenches – 7/16, 1/2, 9/16 are common for bracket bolts and cable ends.
  • Drill and high-speed steel drill bits – for drilling new mounting holes if required (check existing floor pan reinforcement).
  • File or deburring tool – to clean up any sharp edges around holes drilled in the floor or console.
  • Wire cutters, wire strippers, and crimpers – for electrical connections (neutral safety switch, reverse lights).
  • Heat shrink tubing and electrical tape – to insulate and protect connections.
  • Multimeter – useful for verifying correct wiring and continuity.
  • Safety glasses and gloves – always protect your eyes and hands when drilling or working under the dash.
  • Jack and jack stands – you may need to raise the vehicle to access shifter cable routing and transmission linkage.
  • Penetrating oil (e.g., WD-40, PB Blaster) – helps loosen rusty fasteners on the old shifter.
  • Shop rags and a drip pan – expect some transmission fluid leakage when disconnecting the old linkage.

Preparation: Safety First, Battery Disconnected

Park the car on level ground, engage the parking brake, and chock the rear wheels. Disconnect the negative battery cable – this is not optional. The neutral safety switch wiring under the console can deliver 12 volts, and accidental grounding could damage electronics or cause a brief short. With the battery disconnected, you can work safely on the electrical connections later.

If your car has an aftermarket stereo or alarm, make a note of any constant-power wires under the console. It is also wise to take pictures of the existing shifter mounting area and linkage before tearing anything apart; reference photos make reassembly and adjustment much easier.

Removing the Center Console and Old Shifter

Most A-bodies have a center console that is held in place by several bolts or screws – typically located under plastic trim caps, inside the storage bin, or along the sides. Remove the shift knob (usually a set screw or threaded design) and any trim bezels. Carefully lift the console slightly to access the shifter cable or rod linkage underneath.

If your car has a column shift with a cable running to a floor-mounted "slush box", you will need to disconnect the cable from the transmission arm first. For cars that originally had a floor shifter, the linkage is often a rod system that unclips with a retaining clip or spring cotter pin. Label each connection point with tape or take a photo so you can reinstall the new B&M cable correctly.

Once the linkage is free, unbolt the old shifter from its mounting bracket or floor plate. The factory bolts may be rusty – spray them with penetrating oil and let it soak for several minutes before attempting to remove. Lift the old shifter and bracket out of the car as one unit if possible. Clean the exposed floor area of any dirt or rust; this is a good time to apply a light coat of rust inhibitor.

Installing the B&M Shifter

Now position the new B&M shifter in the transmission tunnel. Most kits come with a template for drilling the mounting holes. Tape the template to the carpet or vinyl floor, ensuring the shifter will sit level and clear the transmission bellhousing, driveline, or any underbody braces. Double-check alignment with the seat: you want the shifter to fall naturally to hand without forcing your arm forward or backward.

Drill the holes using the bit size specified in the instructions. Deburr any rough edges with a file. Install any supplied rivnuts or nutserts if required – these provide threaded holes in sheet metal and are much more durable than using self-tapping screws. Bolt the shifter bracket firmly to the floor. On some A-bodies, you may need to modify a small section of the floor brace for clearance; use a hammer and dolly or careful cutting and welding if necessary. However, most B&M kits are designed to fit without major surgery.

Attach the shifter to its bracket. The shifter body should move freely through its pivot range before you connect the cable. Install the shift cable: one end clips to the shifter's lever, the other end connects to the transmission shift lever. Route the cable away from exhaust pipes, sharp edges, and moving suspension components. A cable that is kinked or rubbing against a bracket will cause stiff shifting and premature failure. Use zip ties to secure the cable at intervals.

Adjusting the Linkage for Perfect Shift Engagement

Proper linkage adjustment is critical for both performance and safety. With the shifter and cable installed, put the transmission manually in Park or Neutral (depending on the design). On the B&M unit, move the shift lever to the corresponding position. There is usually an adjustment barrel or a slotted hole on the cable end – tighten the cable so there is no slack, but do not pre-load the lever. The transmission should click into each gear with a positive feel.

Cycle through all the gears (P-R-N-D-1-2) while the car is still on jack stands. Have an assistant watch the transmission lever; each detent should correspond exactly to the shifter's stop. If the shifter feels loose or the indicator is misaligned, re-adjust the cable length at the barrel or change the pivot position on the shifter lever if multiple holes are provided. On many B&M units, you can also adjust the detent spring tension – but leave that at the factory setting until you test drive.

Wiring the Shifter: Neutral Safety and Reverse Lights

Modern B&M shifters include a built-in neutral safety switch and reverse light switch. Follow the specific wiring diagram that comes with your kit. In general, there will be two wires for the neutral safety switch: one connected to the starter solenoid circuit (the wire that only allows the starter to engage in Park or Neutral) and the other to a ground. The reverse light switch wires tap into your car's reverse light circuit – usually a pair of wires running from the reverse lamp to the transmission or the steering column.

If your original car had a column shifter, the neutral safety switch and reverse lights were likely integrated into the column. You will need to bypass or remove the column connections. To keep things simple, you can splice the B&M switch directly into those circuits. Use heat shrink connections or crimp connectors, then wrap with electrical tape or use adhesive-lined heat shrink for a weatherproof seal. Secure any loose wiring with zip ties to prevent it from catching on the shifter lever.

Important: Test the neutral safety function before you reassemble the console. With the shifter in Park or Neutral, the car should start. In any gear, the starter should not engage. If it does start in gear, your switch wiring is reversed or the shifter is not adjusted correctly – do not drive the car until this is resolved. Improper neutral safety wiring is a safety hazard.

Reassembling the Center Console

With the wiring done and the shifter fully operational in park position, reinstall the center console. Place the console over the shifter and secure it with the original bolts. Trim the interior carpet or rubber boot around the shifter base as needed. Most B&M kits include a rubber dust boot that slips over the shifter stick; install that before the console goes back in – it prevents dirt and debris from entering the shift mechanism.

Tighten all hardware to specification and double-check that no wires are pinched between the console and the floor. Reconnect the battery. Cycle through the gears again – the shift pattern should feel smooth, with no binding or interfering with the console. Install the shift knob and set the pointer indicator (if included) so it aligns with the correct gear positions.

Maximizing Power Delivery: Beyond the Shifter

The B&M shifter alone gives you faster, more positive shifts, but to truly maximize power delivery to the wheels you need to look at the entire drivetrain. Below are the most impactful upgrades and adjustments to wring every bit of performance from your A-body Mopar.

Upgrade Transmission Fluid and Filter

Flush out the old transmission fluid and replace it with a high-quality synthetic ATF designed for performance use, such as B&M Trick Shift or Royal Purple Max ATF. These fluids have lower friction coefficients that reduce heat and improve shift response. At the same time, replace the filter and gasket. A clogged filter starves the transmission of pressure, causing lazy shifts and potential damage.

Install a Performance Torque Converter

Your torque converter determines how well the engine connects to the transmission. A stock converter is too loose for aggressive launches and may slip under power. A B&M Holeshot or similar stall converter (typically 2400–3000 RPM stall for a street car) allows the engine to rev closer to its torque peak before the car moves. This dramatically improves power transfer off the line and can cut a full second off your quarter-mile times. Work with a converter specialist to match the stall speed to your camshaft and rear gear ratio.

Check for Vacuum Leaks and Tune the Engine

Nothing kills power delivery like a vacuum leak. After the shifter installation, inspect all vacuum hoses – especially the transmission modulator line (if equipped with a 727, the modulator controls shift firmness). A leaking modulator vacuum line can cause erratic shifts and poor part-throttle response. Replace any cracked hoses and ensure the modulator itself is not damaged. Tune your carburetor or fuel injection system for optimal air/fuel mixture and ignition timing. Even a small increase in peak horsepower multiplied through the transmission yields a noticeable gain at the wheels.

Upgrade the Transmission Modulator and Shift Kit

If you have a TorqueFlite, a vacuum modulator with a sharp rise characteristic (like a Trans-Go shift kit) will increase line pressure and firm up shifts. Combined with your B&M shifter, this eliminates the mushy transition between gears and reduces shift overlap, which wastes power. Follow the kit instructions carefully; some require drilling or replacing valve body components. This is a moderate complexity job – if you are not comfortable inside a transmission, have a professional do it.

Improve Traction and Rear Suspension

All the power in the world is useless if it goes up in tire smoke. With a shorter, firmer shift thanks to the B&M shifter, your rear end will experience a more sudden loading. Upgrade your tires to drag radials or at least high-traction street tires like Mickey Thompson ET Street S/S or Nitto NT555R. Consider adding adjustable pinion snubbers or traction bars (e.g., CalTracs or Mopar’s own HD leaf springs) to control axle wrap and reduce wheel hop. Your shifter and drivetrain mods will be fully realized when the car launches straight and hooks hard.

Lighten the Rotating Mass

Reduce parasitic losses by using an aluminum driveshaft (or a carbon-fiber unit for extreme builds) and lightweight wheels. Every pound you remove from the rotating assembly frees up horsepower that would otherwise be lost to inertia. The B&M shifter makes these gains more usable because you can shift quickly without upsetting the chassis, keeping the engine in the powerband.

Testing and Troubleshooting Your Installation

Before taking your first real drive, perform a thorough test. Start the engine and slowly shift through each gear with the brakes firmly applied. The shift lever should click firmly into each detent. If it feels loose (cable slack) or you have to force it past a stop (binding), re-adjust the cable. Also, check the transmission fluid level with the engine running and the transmission in Park or Neutral. Top off if necessary.

If you have any issues with the engine starting in gear, revisit the neutral safety switch wiring. If the reverse lights do not come on or stay on continuously, check the switch adjustment – the switch plunger must be actuated only when the shifter is in Reverse. Common mistakes include installing the switch upside down or bending the actuator tab incorrectly.

On the first test drive, pick a flat, empty road. Accelerate gently through the gears, then perform a few firm acceleration runs. The shifts should be crisp and immediate. If you feel any slipping or hesitation, you may need to adjust the modulator (TorqueFlite) or check the transmission line pressure. Also, listen for any driveline clunks – that could be a loose transmission mount or improperly adjusted linkage.

Conclusion

Installing a B&M shifter in your A-body Mopar is a rewarding project that improves both driving enjoyment and performance. The key steps – proper mounting, cable routing, linkage adjustment, and wiring – are straightforward but demand attention to detail. Once the shifter is in place, leverage the upgrade by optimizing the rest of the drivetrain: high-quality fluid, a stall converter, correct engine tuning, and improved traction. Each component works together to maximize power delivery, turning your classic Mopar into a more responsive and capable machine. Take your time, follow the instructions, and enjoy the satisfaction of a job well done.

For further reading: B&M’s official site provides spec sheets and online manuals (bmracing.com). Reputable performance parts suppliers such as Summit Racing and JEGS carry extensive Mopar support components. For community knowledge, the For A Bodies Only forum is an excellent resource for troubleshooting specific A-body details.