Tom Wilson
June 1, 2013

Modular to Pushrod

It might seem retrograde, but sometimes racers end up putting push-rod 5.0-and 5.8-based engines in ’96-’04 chassis that originally had 4.6 modulars. In that case, Maximum Motorsports says the easy way out is to use its tubular K-members designed for the ’94-’95 Mustang GTs.

In fact, Maximum says when it comes to engine swaps, the K-member is determined by the engine, not the chassis, because the engine mounts are where the biggest changes are. At the chassis end the difference between Fox and SN-95 K-members is in the hole spacing on the two rear-most legs of the K, and Maximum has all the combinations of engine and chassis covered.

Swap Realities

- Many first-time swappers find the job more involved than expected, and that’s OK. To be meaningful and provide any growth a challenge has to be a challenge. In no particular order here are some things to keep in mind.
- Physically fitting the engine and transmission is the easy part. The devil is in the electronic and plumbing details.
- Aftermarket parts are a wild card no manufacturer can account for. A kit might fit a stock Mustang, but non-stock parts can change that dynamic.
- Cleaning takes time. When the engine is out is the time to scrub, and you won’t be happy with new, clean engine in an old road-spattered engine compartment. Budget generous time and energy for this.
- Modular V-8s are tall and wide. Moving from vacuum to Hydroboost brakes may be required, especially with Four-Valve engines.
- Steering racks on modular engine cars are 1 inch lower than on pushrod engine Mustangs. You’ll need to lower the steering rack and fit matching spindles when fitting a modular to a Fox or ’94-’95 SN-95.
- Chasing small parts eats up 90 percent of the time. It’s almost always easier to order a complete crate engine, or buy an entire parts car and pick it apart at your leisure
- You’ll need shop space. The car will be apart longer than you think and your significant other will soon get tired of an immovable lump where the Christmas decorations belong, so plan accordingly.
- Custom tuning is necessary for drivability reasons if not also for power. Budget $500-$700 for it.
- Engine swaps commonly occur in higher-mileage cars and what you’re really doing with a swap is restoring and hot rodding. Be realistic when evaluating the brakes, tires and suspension of the recipient vehicle and budget for new gear if necessary.
- New engine accessories are typically needed for older cars. It’s easier to replace the starter, radiator and so on when they’re right in front of you rather than buried in the engine compartment.
- Don’t forget hood clearance.
- A new hood means new paint…
- The 2011 and later Mustangs have more complex computer systems that identify the engine’s VIN number several places throughout the car (notably the instrument cluster module). Swapping computers in these cars can be a no-go proposition or require dealer-only connection to the Detroit mothership.
- So far, EcoBoost engines are a non-starter due to electronic issues. Some of the best pros advise us it can’t be done without factory help at this point.

Ford Racing Control Packs

Modern engine swapping and hot rod building has quickly come to revolve around Ford Racing Performance Parts collection of electronics, wiring and hardware known as Control Packs. The idea is Ford puts together a package of parts required to get their crate engines up and running in any vehicle. Typically this includes an engine management computer, wiring harness, throttle pedal assembly, oxygen sensors, mass air sensor, and airbox assembly.

The trick is Ford Racing has flashed the computer with slimmed down software and provided a minimal wiring harness to connect the mass air, electronic gas pedal and computer to the engine, so there is little interface with the chassis. That saves many electronic headaches and makes the crate engine/control pack combination portable among chassis.

Control Packs work with FRPP’s crate engines or donor engines from wrecks, and the Control Pack computers can be custom tuned via the usual OBD-II port. They make it easier—or possible in some cases—for folks swapping engines or building street rods, Cobra replicas, and race cars.