Mustang Project Car

Horse Sense: Building our T-top coupe has been a nonstop process thus far, and it appears there won't be any break if we hope to finish in time for Drag Week. Completing this engine is a major milestone, but it doesn't stop the sand from slipping through the project's hourglass. With that State of the Project address, we keep on pressing.

Building a high-performance small-block Ford engine can be compared with cooking a gourmet meal. In both cases, a lot of time is devoted to preparation, including selecting the best parts or perfect ingredients, and the ultimate goal for each effort is to create a masterpiece that will delight one's palette or, in the case of the engine, quadruple a 'Stangbanger's normal heart rate the instant the bullet is fired for the first time.

Our project was devoid of a drivetrain when we acquired it in October 2005, and we thought it would be cool to fill the vacancy with an engine that has a pseudo Jekyll and Hyde persona. We wanted an engine that was capable of running down the road without a care but was ready to bust off low elapsed times and high speeds at the drop of the right foot, whenever we stopped by a local dragstrip.

For insights on what it takes to build the ultimate dual-purpose powerplant and achieve the best of both qualities, we checked with Keith Craft, of Keith Craft Performance Engines of Arkadelphia, Arkansas. Keith is the man behind some of the baddest small-blocks and big-blocks in all-Ford drag racing and NHRA competition, and Doug Mangrum and Joe DaSilva are just two names on the long who's-who rundown of well-known racers using engines prepared by Craft Racing.

In our introductory story about this project ("Raisin' the Roof," May '06, p. 94), we told you that our Drag Week effort is being made in the spirit of the old school-the middle '90s-and what we vets consider the pioneer days of hardcore 'Stangbanging. Back then, many of us lived for driving-not towing-our Ponies to the track, with the hatch or trunk loaded with slicks, jacks, and tools. Then, when our day at the drags was over, we'd get back on the road to our homes or maybe some other clandestine, after-hours racing location.

Drag Week is Hot Rod's five-day street/strip endurance challenge that puts gearheads to the test of traversing roughly 1,500 miles across the Midwest in early September in an effort to determine who has the hardest-hitting "street car" in the country. The car must be registered and insured, with functioning headlights, taillights, brake lights, turn signals, and horn.

Keith and Jeff Henry, Keith's lead engine assembler and shop foreman for the last 13 years, offered their thoughts on what we'd need to build a modern-day 347ci engine capable of handling the demands of Drag Week and thousands of street/strip miles thereafter. "You can build a 347 with a stock block, but if your budget can stand it, the aftermarket-block/big-bore 347 is definitely the way to go," Jeff said. "It's a better all-around package for a street engine because it's simply a lot more durable."

As many of the old-timers probably remember, stepping up to a 347 stroker back in the day was the easy way for budget-conscious 5.0 enthusiasts to gain more horsepower and a ton more torque with a 302 block. This mod is derived from a 0.030-inch-overbore, 3.400-inch-stroke crankshaft and 5.4-inch connecting rods. It didn't take long for it to catch on as the preferred engine upgrade for those of us who wanted power-adder-like performance from a naturally aspirated mill. It also appealed to serious racers who knew the true, warp-speed potential of a blown, turbocharged or nitrous-injected stroker with an aftermarket block.

A stout 347 puts torque under a 'Stang's hood that can certainly hold its own if compared with the low-end grunt of a mildly worked 351 Windsor. The bottom line is, additional cubic inches created by increasing stroke-the total distance between the center of the crankshaft and the center of a rod journal when a piston has fully traveled from bottom dead center to top dead center-with a bigger crankshaft, longer connecting rods, and shorter or longer pistons, is an easy way to boost the torque potential of a small-block Ford. The simplicity of stroking is another factor that made the upgrade popular then and now. While we're stroking our 'Stang's engine, we're also approaching things a bit differently when it comes to the bore.

Thanks to the refinement of aftermarket engine blocks and the astounding limits to which they can be bored, the "big-bore" small-blocks Jeff mentioned earlier are gaining steadily in popularity. The 0.185-inch maximum bore size for a Ford Racing Performance Parts R302 is light years beyond the 0.060-over threshold that was possible, but not recommended, for daily driven 8.2-deck 302s years ago. Opening up a 5.0's 4.00-inch cylinder-bore size by 0.030, 0.040, 0.060, 0.100, or 0.125-inch increases cylinder volume, and thus has an impact on an engine's overall cubic inches-another route to torque gain.

Larger cylinder bores and the pistons that go with them allow many of today's aluminum cylinder heads to work more efficiently as well. According to Jeff, a big-bore piston's taller compression height-1.165 versus 1.100 inches of a 3.400-stroke 347, for example-helps keep it more stable inside the bore at high speed. "The standard, 0.030-over 347 pistons have small skirts and they tend to wear quite a bit because the piston actually rocks slightly as it travels inside the cylinder," he says. "The big-bore/short-stroke combination can make the same displacement you're looking for and will prove a more durable combination, mainly because of the increased stability of the pistons." With that in mind, we decided to go with the 4.125-inch big-bore for the T-top coupe's new 347.

It's important that our engine package is designed to make efficient use of parts that are available directly from the shelves of Craft Racing, Summit, Jeg's, the manufacturers, or other retailers. With a project like this, we realize the door is open wide for creating a mega-dollar dream engine, but we've elected to shut that door and present a powerplant that, for the amount it costs to produce, will be a great value and will easily handle your street/strip needs. Of course, we're expecting grunt down low and great performance upstairs from the cubic inches that will be joined by the Paxton Novi 2000 supercharger we plan to add once the engine is in. But no-fuss, standard-maintenance-only durability is also an important part of this effort.

The engine is complete and will probably be in the car by the time you read this, but we still have several areas of the build to cover, so be sure to stay tuned each month. For now, read on and learn more about the makeup of our rare 'Stang's new bullet and our introduction to the new XFI engine-management system by Fuel Air Spark Technology we're using to tune it.

A good aftermarket 8.2- or 9.5-deck block is the only foundation to consider for building any small-block with a 0.060-inch or greater bore size. We went with this R302 casting from Ford Racing Performance Parts (PN M-6010-R302) for our 347. The "R-block," as it's referred to by Ford racers everywhere, is a stronger, thicker alternative to the standard 302, which is prone to failure under the stresses of major power. As seen here, there's also plenty of room in the crankcase area of an R-block, so setting up a long-rod stroker with as many as 360 ci wouldn't be a problem with a 0.125-inch overbore and the 3.400/5.4-inch (347ci) crank-and-rod package. Aftermarket race blocks such as this require machining before any engine assembly can be done. In addition to opening up the cylinder bores, the crew at Keith Craft Performance Engines cleaned and prepared our block by "squaring the deck and torque-plate honing the cylinders, honing the lifter bores, notching the block for stroke clearance, line honing and installing cam bearings, and inserting oil-gallery plugs," according to Tony Loy, our point man at Craft Racing who played a big role in getting us on the schedule for engine assemblies.