KJ Jones
December 31, 2013
Photos By: KJ Jones
Like the headers, the X-shaped crossover bolts-in without any need for modifying or radical finagling, and mates with the ’Stang’s original after-cat hardware.
Once the headers and X-shaped crossover are installed, Ricardo starts the engine and checks the exhaust system for any audible leaks.
After exhaust installation, tuning, and dyno testing (see On The Dyno), we focused on applying the standard group of basic bolt-ons to our project engine, starting with underdrive pulleys. On 4.6-liter Two-Valves, smaller- (crankshaft) and larger-diameter pulleys are used to reduce the amount of horsepower that’s necessary for driving a ’Stang’s belt-driven accessories (alternator, water pump), by allowing the crank pulley to turn several times before those accessories’ pulleys rotate even once.
BBK’s CNC-machined, three-piece underdrive pulley set (PN 1564; $269.99) is highlighted by an SFI-approved, steel crankshaft damper. This system is designed to directly replace the stock pulleys, to reduce drag and ultimately uncover approximately 10 rear-wheel horsepower. One of the big changes that we noticed with this set is that the damper is updated; it is now a one-piece unit, as opposed to a piggyback-style pulley. Despite the change, the system is still uses the ‘Stang’s stock-length serpentine belt.
BBK’s 5-inch damper shaves a whole 2 inches from the factory crankshaft pulley …
… and conversely, at 6 inches in diameter, the new aluminum water-pump pulley is an inch larger than the stock wheel.
The alternator pulley measures slightly smaller than OEM. However, it must be noted that our test Bullitt uses the same alternator as a Cobra, not a Two-Valve Mustang GT. Because of this difference, we’re not able to install the BBK wheel for our application.
Pulleys are relatively quick installs. While a specific tool is needed for extracting the stock crank pulley, the water-pump wheel is secured with four bolts, and literally can be changed in minutes.
Improving intake airflow is the hands-down leader of the basic mods for late-model, V-8–powered Mustangs, and making such improvements starts with eliminating the stock airbox and filter.
This slick-looking, cold-air-induction set comes from BBK’s new Black Out series of CAIs (PN 17185; $199.99). The kit features all-black tubing, a high-flow, conical air filter, couplers and all of the hardware necessary for a direct-fit replacement of the factory airbox on Two-Valve GTs.
A new, larger throttle body also makes up a big part of the “air-in” side of an entry-level-bolt-ons project. The BBK twin-bore, 65mm ‘body (PN 1711; $349.99) is actually a Cobra-purposed part that’s 8mm bigger than the ‘Stang’s original, 57mm unit. The throttle body is machined with thicker walls (at the top and bottom) for improved mating with inlet tubing and couplers, and includes an OEM throttle linkage, double-sealed bearings, and an O-ringed throttle shaft.
Throttle body installation requires exchanging TPS hardware from the stocker, and securing the BBK unit to the Bullitt’s plenum, using a gasket and fasteners that are supplied.
The CAI assembly is straightforward, with Eddie only needing to attach the Bullitt's OEM mass-air housing to the new Black Out inlet tube, and install it and the filter in the 'Stang's passenger-side fender. However, the CAI's mass-air-to-throttle-body tubing is specific to Mustang GTs, and unfortunately could not be used with the Bullitt's intake plenum. With time working against us, we were forced to reinstall the factory mass-air-to-throttle-body tube for this test.
The CAI assembly is straightforward, with Eddie only needing to attach the Bullitt's OEM mass-air housing to the new Black Out inlet tube, and install it and the filter in the 'Stang's passenger-side fender. However, the CAI's mass-air-to-throttle-body tubing is specific to Mustang GTs, and unfortunately could not be used with the Bullitt's intake plenum. With time working against us, we were forced to reinstall the factory mass-air-to-throttle-body tube for this test.
For those who are installing a Black Out kit on Two-Valve GTs in California, here is a bit of good news. The no-tune-required kit is 100-percent CARB-approved (that’s smog-legal in Cali jargon).
Ready for the dyno … again.

Horse Sense: At this point, we've proven many times that making changes on a basic level—across all late-model-Mustang platforms—definitely yields marked improvements in performance. Results of our studies also show that intake-and-exhaust components—arguably the core entry-level, upgrade pieces—are quite affordable nowadays (especially for pre-Coyote Ponies).