Many of the classic Ford cars we love came equipped with six-cylinder engines. A popular choice in Falcons and Mustangs, they offered acceptable street performance along with good fuel economy.
Early in Mustang sales, the six-cylinder cars were often the only ones on the showroom floor as the V-8-powered models were sometimes not available. The 170, 200, and 250ci sixes were all based on the original 144ci six-cylinder engine which debuted in the '60 Falcon. With a bore of 3.50 inches and a stroke length of 2.50 inches, the 144 was low on grunt and slow on acceleration. The stroke was lengthened to 2.94 inches in 1961 to yield a displacement of 170 ci. In this incarnation, the engine was rated for 105 hp. In 1964, both the bore and stroke were enlarged to 3.68 inches and 3.126 inches, respectively. The displacement for this combination was 200 ci.
Until this time, these engines had a four-journal saddle for the crankshaft. In the middle of the '64 production run, the block was recast to incorporate seven journals for the crankshaft. With nearly double the crank support of the earlier version, the new inline-six was much more durable. The seven main-bearing design was a more durable engine with some performance potential. Later, in 1969, the block deck height on the 200 engine was raised 1.66 inches and the engine stroked to 3.91 inches for a displacement of 250 ci. Many of the components from the bigger six, which saw extensive use overseas, particularly in Australia, are interchangeable with the earlier engines.
If your classic Ford has a six-cylinder engine, and you've been thinking that your car will never be quick without going to a V-8, think again. There are many interesting performance possibilities out there. Let's take a look at some of the more popular upgrades and conversions that are being done on six-cylinder Fords. We think you'll be amazed at the ingenuity and craftsmanship.
Six on the 'Net
No, I said six, so get your mind out of the gutter! If you're looking for some great information on six-cylinder performance, maintenance tips, or you just want to trade barbs with your fellow six-hole enthusiasts, check out www.fordsix.com. There you'll find interesting six-cylinder-based tech articles, a thriving member forum, a members' ride section, and more. So if you've got a hankerin' for any of the Ford six engines and an Internet connection, drop by www.fordsix.com and say "hi" to the gang.
Here's a bone-stock, 200ci...
Here's a bone-stock, 200ci six-cylinder engine as it might appear installed in a Falcon or Mustang. The single-snorkel air-cleaner housing conceals a wheezing, single-barrel carb that's designed just for fuel economy.
To begin our journey to six-cylinder...
To begin our journey to six-cylinder performance, we need to improve over the little one-barrel carb found on the stock engine. This intake manifold has been modified to accept an adapter for a two-barrel carb.
This shot shows the adapter...
This shot shows the adapter plate in place on the manifold, topped by a tapered spacer plate, and finally the carb baseplate. A variety of adapter plates are available at your local performance equipment outlet and range in price from $12.75 to $55.00 depending on the application. Trans-Dapt PN TRD-2044 adapts a Holley two-barrel to a single-barrel manifold for $32.95. Trans-Dapt PN TRD-2065 adapts a four-barrel carb to a two-barrel inlet for $14.75.
If stepping up intake capacity...
If stepping up intake capacity even further is in your plan, then check out this Holley 600-cfm four-barrel carb on a modified two-barrel intake. Again, the manifold comes from the Ford Australian 250ci engine. A Holley four-barrel like this one costs $236 new and is PN 4160-1850C.
Many successful multiple carb...
Many successful multiple carb installations have been made on the Ford six. This three one-barrel arrangement uses an Offenhauser intake manifold and YF carburetors. It provides the wow factor yet still has good driveability and throttle response. The triple one-barrel intake is still available as PN OFY-5205. We found one new for $246.
If you were thinking we had...
If you were thinking we had run out of induction possibilities for your Ford six engine, then keep your seat. This six-cylinder aluminum intake has been modified to accept an EFI throttle body. Bungs for fuel injectors have been welded into place directly above the intake ports. The fuel rail has been welded to the intake above the injector ports and is ready to go. An Edelbrock 70mm throttle body similar to this one is PN EDL-3825 and cost $209.88.
Here's a custom intake manifold...
Here's a custom intake manifold made to accept this Garret turbocharger. With a straight-six engine there's extra room under hood for these turbo installations, and they are becoming more popular. Prices for complete turbo-charger kits range from $3,399 to $5,400, and must be custom adapted to specific classic applications.
When one atmosphere just isn't...
When one atmosphere just isn't enough, there's always the trusty centrifugal supercharger. This big Paxton unit looks like the correct vintage for this engine, and it seems right at home hooked up to the 350-cfm Holley two-barrel. An equivalent Novi 1200 supercharger kit costs $2,739.
On the exhaust, the first...
On the exhaust, the first improvement is the installation of a center port divider. In the stock configuration, the two middle cylinders empty into a common exhaust port, causing turbulence and robbing power.
This center port divider is...
This center port divider is available at Clifford Performance. It is PN 73-1136 and costs $13. The insert divides the center exhaust port into two separate chambers, eliminating turbulence and smoothing out exhaust flow. Trim and shape the part to fit your center exhaust port.
Here is the center port divider...
Here is the center port divider welded into place. Now each of the center cylinders has its own exhaust port out to the manifold. Clean up the passages around the divider to smooth out exhaust flow.
When you step up to headers,...
When you step up to headers, there are two different configurations from which to choose. The first is six-into-one, while the second has two separate three-into-one pipes for a true dual-exhaust system. The header on this engine is the three-into-one type. Ford Six Performance Parts has them painted or coated. PN FSD 200DOH, the header costs $275 unpainted and $375 with high-temperature coating.
Here's an under-the-car view...
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...
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...
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...
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...
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...
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...
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.