Stolen Goods hasn't seen the...
Stolen Goods hasn't seen the road for some time. That's about to change.
Stolen Goods, our '93 Cobra project has created quite a stir in the Mustang community. Our almost unreal find of an SVT machine had a mere 1,300 miles on the clock, but the drivetrain was missing and we had to rebuild it and give it a new life. In the past few months, we got the car off blocks, and it's rolling again. Now it's time to get the heart of the snake beating-and since late-model Cobra Mustangs were essentially factory hot rods, we went back to the factory to find a suitable powerplant.
A Cobra By Today's Standards
In bringing Stolen Goods back from hibernation, we wanted to achieve a performance level greater than that of the original '93 Cobra-or the R model, for that matter. When it comes to exceeding the factory engine output, that may be one of the easiest things to accomplish. Though the '93 Cobra and Cobra R powerplants were rated at a mild 235 hp, the same GT-40 components that SVT bolted on the engine were known to produce closer to 270 in independent tests. But even the latter mark is easily surpassed given the bountiful aftermarket of go-fast products.
If you look to 1995, the 351-powered Cobra R was still rated at only 300 hp. You have to move on to 2001 for more power, when the modular-powered Cobra R model's 5.4L, DOHC powerplant thumped out 385 hp and 385 lb-ft of torque. That's a stout number, but one we think Stolen Goods can eclipse, all while keeping the engine civilized and maintaining the broad torque curve 5.0L Mustangs are famous for.
From the beginning of this project, we never planned to do anything overly radical to our resident '93 Cobra, as we wanted a reliable and rock-solid platform to provide plenty of hours of high-performance fun without a lot of maintenance. Therefore we opted to go the naturally aspirated route with the engine. No blower belts to deal with, no trick fuel system needed, and no intercoolers or nitrous bottles to worry about, just raw horsepower and torque, all of the time. With that decision made, there were two ways to build the motor. We could design a high-revving 306, a stroked 302, or go with a big small-block Windsor.
To end up with a nice balance for open track, autocross, street, and strip driving, we set a goal of 400-425 flywheel horsepower. Another stipulation your author made was that Stolen Goods would have to make do with a 3.27, or at most, a 3.55 gear to keep the revs down on the highways. That pretty much ruled out the high-rev idea since the engine would spend far more time in the low and mid-rpm range. We also wanted to keep the stock hood, and while we've seen 351s fit under one, it usually came with great effort and mods to other items like the K-member to achieve this. So the Windsor was out.
Going with an 8.2-inch deck-height block would be the ideal choice, and since your author spends more time striving for deadlines than he does building engines, we turned to the Ford Racing Performance Parts catalog in search of an assembled short-block.
Ford Racing Performance Parts'...
Ford Racing Performance Parts' new Boss block (PN M-6010-BOSS302) retails for $1,759 and features numerous improvements over older designs. How much power do you want to throw at it? FRPP's not afraid.
Part number M-6009-C347 is a 347ci stroker short-block assembly that uses a Sportsman two-bolt main block along with forged pistons, connecting rods, and crankshaft. That seemed like a pretty good choice, and it might be for many of our readers. We contacted Jesse Kershaw of FRPP to get his opinion and talked with him about our engine's intended use. That's when he offered us one of FRPP's new Boss engine blocks.
The Boss is Back
The new Boss block (PN M-6010-BOSS302) was designed with input from Ford's NASCAR engineers and from information gained during Ford's involvement in the ASA racing series. The Boss is set to be the basis for all of FRPP's crate engines in the near future, and it will be available as a bare or assembled short-block as well. At the time we went to print, assembled block production was still in its infancy. In fact, we received one of the first 150 blocks produced.
Its major features include four-bolt splayed caps on the number 2, 3, and 4 main crankshaft journals, screw-in, O-ringed freeze plugs and oil galley plugs, 11/42-inch main cap and head bolts, and a diesel-grade, nodular-iron casting that can be bored and stroked out to 363 ci. It is 16 pounds lighter than the R302 block it replaces and retails about $240 cheaper at $1,759.
Since we're not professional engine builders, we contacted Tom Naegele at D.S.S. Racing in St. Charles, Illinois, about constructing our snake's short-block. D.S.S. had assembled the 331ci Super Bullet bottom end in our project ProCharged Pony a few years ago, and the engine has handled everything we've thrown at it, so we knew it would be up to the task of building Stolen Goods' powerplant.
Naegele's plans for the Boss block includes using D.S.S. Racing's brand-new horizontal machining center to perform its CNC Level 20 blueprinting, giving us a state-of-the-art hunk of iron to use as the basis of our buildup. He also gave us his take on FRPP's new offering and expounded on some of its features as well as what D.S.S. plans to do to the new hunk of iron.
The new Boss 302 block weighs...
The new Boss 302 block weighs about 32 pounds heavier than a Sportsman block, yet it's 16 pounds lighter than the R302 chunk of metal. It can be taken out to 363 ci and requires a minimum amount of work to sling the stroker assembly inside it.
Splayed main caps on journals...
Splayed main caps on journals 2, 3, and 4 will help keep the bottom end together under severe duress. The new Boss also employs 1/2-inch-diameter cap bolts for superior strength.
The Boss 302 utilizes common...
The Boss 302 utilizes common OD cam bearings or conversion bearings for use with most off-the-shelf cams. Stock cam journals, however, are all different sizes. Most cam companies offer common OD cams through special order, but FRPP came up with conversion bearings (PN M-6261-J351) to facilitate the use of common, off-the-shelf 302/351W grinds.