Six-Cylinder Engine Performance - Inline Power Potential

Here's an under-the-car view of the six-cylinder, dual-exhaust system. We like this arrangement better than a six-into-one pipe setup because it provides dual pipes all the way to the back of the car, and it has a nicer sound. The "x"-type crossover incorporated into the system smoothes exhaust flow. Follow the example in this photo, and you can't go wrong.

This bare 200 six-cylinder head after cleanup shows the relatively straight shot down the intake port to the valve. The engine flows well on the intake side.

This view of the cylinder head shows the exhaust side with the relatively small ports. The runner is more twisted than on the intake side, and work on the exhaust side of the engine will be worthwhile. We have measured the flow capacity on this head and have seen significant improvement when intake valve size was increased from 1.649 to 1.75 and the exhaust valve was enlarged from 1.388 to 1.50. These upgrades and a general port cleanup improved flow figures significantly. Flow capacity rose from 170 cfm to 190 cfm on the intake side and from the stock 110 cfm to 135 cfm on the exhaust side.

Cam selection for your six-cylinder project depends entirely on how the engine will be used. If you choose to install these fully adjustable aluminum shaft rocker arms, your valvetrain will be up to any cam selection. The roller-tipped units shown here have a ratio of 1.6:1 and come fully assembled. Getting them onto the engine is a simple bolt-on procedure. They're PN RAS-200-RTR and cost $415 per set from Ford Six Performance Parts.

Finish off any valvetrain upgrade with a double-row timing chain, available at FSPP under PN JPP-200-DRC. The set costs $99 and will guarantee a stable timing adjustment.

This new finned aluminum valve cover will look good while protecting the valvetrain. It's PN FSP-200-AVC at Ford Six Performance Parts, with a retail price of $170.

Getting DizzyDavis Unified Ignition is currently at work finishing the details on a DUI distributor for the small Ford six-cylinder engines. This distributor is made to fit the shorter deck version of the engine with the 170ci and 200ci displacements. Performance Distributors already makes a DUI distributor for the larger 250ci six, so now Davis Unified Ignition distributors will be available for both six-cylinder engines. Both part numbers will be available at FSPP. The DUI distributors are capable of stand-alone operation or are fully compatible with aftermarket ignition boxes. They are a one-piece, drop-in unit with the coil and ignition module already in place, and they are equipped with both upper and lower bushings for durability. The DUI requires only one hot lead to the distributor, and a 50,000-volt spark will be generated. This allows for a super-wide 0.055-inch plug gap for positive ignition. Expect the pricing on the new distributor to be between $325 and $400.