Mike Winterboer will tell you a '69 six-cylinder SportsRoof isn't worth a flip unless the platform and engine work cohesively. He sent us a dream sheet, and we went to work contacting friends in the industry willing to help.
When Mike Winterboer of Classic Inlines called us about this project a year ago, we were excited. It wasn't a stump-pulling 427ci small-block, nor was it some high-revving 32-valve modular V-8 swap. It was a '69 L-code 250ci Mustang SportsRoof with a big inline-six. While swapping in a V-8 would have been less trouble and perhaps more interesting for most people, Mike decided to stick with the six-building a 250ci tall-deck stroker (272 ci) with a new, aluminum, high-swirl head; electronic fuel injection; and a whistling 50,000-rpm intercooled turbocharger.
After our discussion with Winterboer, we hung up the phone and concluded this was a terrific idea to sink our editorial teeth into-a lightweight, fuel-injected gray-iron inline-six sporting intercooled turbocharger power and a lot of stroke yielding all kinds of torque. What's more, it was high-tech, with the economy and efficiency of electronic fuel injection. He never had to sell us on this idea, it sold itself. This inline twisty project was a golden opportunity to try something new and learn a thing or two about Ford sixes in the process.
So why do something like this? In a world of redundant small-block projects, peppered with big-block and mod-motor undertakings, Winterboer's decision to build a turbocharged six-cylinder Mustang was intriguing. We liked the idea of an underdog six-cylinder Mustang getting all kinds of respect on the racetrack and at car shows.
Most people think of inline six-cylinder engines as wimpy, underpowered dinosaurs. However, those who remember the '60s know different. Fast six-cylinder drag cars were commonplace 40 years ago. There were Ford Falcons and Mercury Comets with three one-barrel induction systems. Chrysler racers brought out multicarb and Hyper-Pak Slant Sixes. There were also Chevy IIs and AMC Ramblers with badass inline-sixes cracking 11- to 13-second quarter-mile times in an era when these numbers were considered fast. Clifford Performance, Clay Smith Cams, Offenhauser, and a host of others supported the high-performance-six marketplace in those days. Racers eager to be different built six-cylinder drag cars. It became a subculture to be reckoned with.
Even today, the venerable inline-six remains in solid, consistent use around the world. Chrysler still offers the American Motors 258ci (4.0L) inline fuel-injected six in its Jeep line. General Motors offers an all-new inline-six in its Chevy Trailblazer sport utility. For a short time during the '80s, Ford was experimenting with a stillborn inline-six for T-drive applications, and that's because inline-sixes offer abundant vibration-free torque.
Pound for pound, inline-six engines make more torque than V-8 and V-6 counterparts because the six bores slap out a beat along a long crankshaft. This is why inline-sixes (and eights) were so common. Straight-eights, as they were called, offered much smoother operation than V-types-so smooth, in fact, that you could stand a quarter on the air cleaner and it wouldn't tip over. They idled at under 500 rpm, and you could lean on the throttle at low rpm and make all kinds of torque. The same can be said for inline-sixes, which offer exceptionally smooth operation when properly tuned.
The small Ford sixes (144, 170, 200, and 250ci) struggle with smooth operation because they suffer from induction-system shortcomings-that frustrating integral log manifold parked right on top of a hot exhaust manifold. Excessive heat around the carburetor coupled with poor fuel distribution along the manifold make Ford sixes challenging to tune.
So what to do about Ford six tuning challenges? Winterboer, along with the assistance of a committed, talented circle of friends, has begun answering this question by developing products and technology designed to improve Ford six performance. Field testing, coupled with old-fashioned seat-of-the-pants racing is what makes great performance products. Winterboer is working closely with friends Will and Kelly McLearran of Tucson, Arizona, to develop six-cylinder performance parts. Will and Kelly approach six-cylinder Fords by going with what works. Kelly's 10-second Falcon sedan is ironclad proof these folks know what they're doing. We had the good fortune of working with Winterboer, the McLearrans, and Kelly's brother, Brian Tuuri, on this project.
From left to right are Kelly and Will McLearran, and Brian Tuuri of McLearran Racing in Tucson, Arizona. Through a passion for powerful classic inline-sixes, these folks have built a nice business-and a 10-second classic turbo Falcon sedan with a carbureted six. | 
Thunder and lightning raged close by when Winterboer arrived with this Maaco-painted '69 L-code six-cylinder SportsRoof. The Mustang Shop invited him in, with all of us ready to build inline greatness. | 
You've got to love this Road Race-R upper and lower control-arm package from OpenTracker Racing Products. Although these pieces resemble what Ford offered from the factory, that's where it ends. Designed for serious roadwork and street performance, Road Race-R arms are made with chromoly-steel shafts and super-tough, replaceable roller bearings. |
Road Race-R lower control arms from OpenTracker Racing Products are specially modified and strengthened for road racing or twisty street work and are fitted with spherical bearing pivots. If you're working on a '67 Mustang, use '68 strut rods for proper fit because these arms are drilled for '68-'70 strut rods. | 
Roller-bearing spring perches from OpenTracker Racing Products offer exceptionally smooth operation, without the traditional "popping" heard from classic-Mustang front suspensions. These control arms and spring perches are fully articulating for smoothness and precise control. | 
OpenTracker Road Race-R arms are easy to install and adjust. We like the Battleship Gray finish, which ties them to the car's gray appointments. |
They require virtually no lubrication or maintenance over the life of the part. | 
Edelbrock gas shocks from Mustangs Plus dampen the ride and improve handling all around for excellent road racing performance. | 
Stam Bar makes an adjustable rear sway-bar setup for classic Mustangs. Designed for street and strip tuning, Stam Bar sway bars install easily and adjust for virtually any condition. Their quality is exceptional. |