Eric English
August 2, 2012

Without a doubt, the mainstream approach to adding horsepower to a vintage Mustang invariably revolves around increased displacement. There may be a blower or nitrous shot that eventually augments, but a "bigger is better" mantra is ingrained in most of us with no hope of ever turning back. For example, unless limited by sanctioning body rules, does anyone really build a stock cube 289 anymore? How about that easy swap to the big brother 351, or while you're at it, why not a 408? Big-blocks anyone? While you could argue that the increasing frequency of high-tech mod motors bucks the mindset, the consistent theme of V-8 architecture and stroker cranks keep these choices well within a framework we're familiar with.

Completely out of the box is the idea of dropping displacement and cylinder count all in one fell swoop. Just imagine swapping out a 5-liter V-8 for a 3.8L V-6. Interested? How about downsizing from 200 cubes to just 140? Nope? Well, Brian Fitting said yes to this exact question when building the '66 coupe he'll give to his daughter someday, and he's not afraid to tell about it.

Now lest you think the choice was made as a move to keep power low for safety's sake, let's clarify what found its way under the hood. What Brian made work in this '66 may be a first for a first-gen Pony--an intercooled and turbocharged SVO 2.3-liter four-cylinder. The genesis for the project seems to have come through personal experience with a couple of mid-'80s 2.3-liter turbo Fords. A combination of good fuel economy, handling, and power left Brian wondering how a similar powertrain would perform in an early Mustang with 500 pounds less bulk. It's one thing to wonder, and quite another to actually find out, but Brian obviously pursued his curiosity to fruition.

Photo Gallery

View Photo Gallery

Of course, no enthusiastic hot rodder leaves well enough alone, and so this overhead cam four-banger sports an 0.020-inch overbore, and CP forged pistons that yield a boost-friendly 8.5:1 compression ratio. The ported cylinder head features 1.89-inch intake/1.59-inch exhaust valves, which are teamed with a Boport 1.0 camshaft and adjustable cam sprocket. Aside from the ATR header, that's about all there is to tell about the actual engine, other than the fact that Brian screwed it together on his own, and backed it with a '90 A4LD four-speed overdrive automatic. But with an SVO turbo, the nuts and bolts of the physical engine are only part of the story, and Brian is quick to thank everyone at who gave him help and encouragement along the way.

In this case, induction comes from a ported SVO intake and stock throttle body, while the turbo was upgraded to a T3/T4 unit teamed with a Spearco intercooler, Garrett wastegate, and two-stage BoostValve boost controller--allowing max boost to change from 10 psi to 25 psi at the flick of a dash-mounted switch. The whole affair gets its marching orders from a Brian Macy–tuned F.A.S.T. EFI system, and is reported to put down a healthy 300 horses at the rear wheels. Brian says this was with an ill torque converter and malfunctioning wastegate, so today's net may be even better.

The starting point for the whole project was a well-used '66 coupe--originally fitted with a Sprint package 200-inch inline six, and factory Pony interior. We were more than a little impressed to learn that Brian did all the work himself--including the replacement of the floorpans, the bodywork, paint, building the engine, exhaust, and removing the shock towers during installation of a Heidts independent front suspension. The latter was surely an upgrade, but Brian also says it was a necessity due to the width of the turbocharged 2.3's supporting hardware. The suspension upgrade includes rack-and-pinion steering and disc brakes, and was paired with a Heidts four-link rear suspension that hangs a 3.50-geared 9-inch fitted with FRPP discs. Rolling stock comes in the form of a set of price-friendly 16-inch '06 V-6 takeoff wheels, shod in Kumho rubber.

Eighteen-year-old daughter Shelby (we're told she's not named after another famous Shelby) surely has the genetic disposition of her father, for rather than go with a traditional Mustang hue, she picked out the '08 Jeep Rescue Green which Brian laid down using PPG Deltron 2000. It's a bold choice to be sure, and one that father and daughter say gets rave reviews--primarily from women. The G.T.140T callout in the stripe is a play on the 2.3's cubic displacement, but Brian laughs when recounting the multiple admirers who have related how they remember seeing a car "just like this" in years past. Sure you did!

Clearly the least risky portion of this '66 is the interior, as Brian and Shelby both felt the bones of the factory black Pony interior were worth keeping. The seats use TMI's sport seat foam and upholstery, which Brian raves as a huge improvement over original. Other well-chosen upgrades include the '65-Shelby-style gauge pod filled with Auto Meter instruments, a Flaming River tilt steering column, and a Custom Autosound trunk-mount stereo, which powers a quartet of Infinity speakers. The deluxe wood steering wheel is standard Pony interior issue, while the underdash A/C assembly is period correct--and mated to the '80s-era compressor under the hood. Sharp eyes will note the apropos four-wheel-disc logo on the brake pedal, which Brian sourced from a Lincoln Versailles.

With Shelby now at 19 years of age, we asked Brian when the big gift would actually be given. He said he'll sign over the one of a kind coupe once Shelby gets her college degree, so he's got at least a couple more years at the reigns of this unusual Horse. With all his talent though, we suspect Shelby will still be leaning on good ol' dad even when her name is on the pink slip. In the meantime, you might say the incentive for finishing school is a bit greater than normal. Hey, Shelby, hang in there and keep your eye on the prize!

Photo Gallery

View Photo Gallery

The Details

Brian and Shelby Fitting's '66 Mustang coupe


  • '86 2.3-liter iron block, 142 cubic inches
  • 3.80-inch bore
  • 3.13-inch stroke
  • Stock SVO crankshaft and connecting rods
  • CP pistons
  • Ported factory cylinder head, oversized 1.89-/ 1.59-inch valves
  • Boport 1.0 camshaft
  • Ford OEM rockers
  • SVO throttle body
  • SVO aluminum intake, ported
  • Ford distributor
  • F.A.S.T. EFI, tuned by Brian Macy
  • MSD 6AL ignition
  • Garrett T3/T4 turbocharger, Spearco intercooler, Garrett wastegate, two-stage BoostValve boost controller


  • ATR header
  • Owner-fabricated 3-inch downpipe and 2½-inch dual exhausts
  • Dynomax mufflers

Fuel System

  • '69 20-gallon tank
  • Walbro 255lph in-tank electric pump, -8/-6 lines
  • Delphi 85-lb/hr injectors


  • '90 A4LD four-speed automatic by Central Transmission


  • Lincoln 9-inch rearend, narrowed by Bill Scribner
  • Nodular case
  • Four-pinion Traction-Lok differential
  • 3.50 gears


  • Front: Heidts Mustang II IFS with rack-and-pinion
  • Rear: Heidts four-link with coilovers and Panhard bar


  • Front: Heidts 11-inch disc
  • Rear: FRPP 11.8-inch disc
  • '96 Mustang hydroboost and master cylinder


  • Front: '06 V-6 Mustang, 16x7-inch alloy
  • Rear: '06 V-6 Mustang, 16x7-inch alloy


  • Front: Kumho Ecsta SPT, P225/55ZR16
  • Rear: Kumho Ecsta SPT, P225/55ZR16


  • Original Pony interior upgraded with TMI sport seat foam, upholstery, and headrests; A-pillar and Shelby dash pods with Auto Meter Carbon Fiber series gauges; Flaming River tilt steering column; Custom Autosound CD player; Infinity speakers


  • '08 Jeep Rescue Green, aftermarket Shelby-style front lower valance, custom rocker striping