Building A 931-Horsepower 5.4-liter On A Budget

 

With the first crop of modern Shelby GT500s reaching 10 years of age, those which were driven hard might be due for some freshening. This 2007 GT500 owned by VMP Performance’s BJ McCarty might be named Christine, but she is certainly not a garage queen, as the car was driven hard on the drag strip and run hard on the dyno.That hard use meant it was time for a fresh engine and VMP wanted to develop an affordable way to refresh these venerable powerhouses.

Here is Christine’s new heart transplant looking right at home under the VMP Gen2R TVS supercharger and its new custom coil covers. Though it looks stock, the revamped 5.4 is far better suited to support high power levels on a consistent basis.

Here is Christine’s new heart transplant looking right at home under the VMP Gen2R TVS supercharger and its new custom coil covers. Though it looks stock, the revamped 5.4 is far better suited to support high power levels on a consistent basis.

It seems as though everyone has this 800-rear-wheel-horsepower goal now and frankly that’s not a realistic number for a stock engine. — BJ McCarty, VMP Performance

“We discussed this and saw it as an opportunity, for ourselves and our customers. We’re not going to infringe on outstanding builders like L&M Racing Engines and that’s certainly not our objective. But, it seems as though everyone has this 800-rear-wheel-horsepower goal now and frankly that’s not a realistic number for a stock engine (at least not very many times),” BJ, VMP’s General Manager, explained. “So, we decided to do this as a ‘budget build’; one that the average GT500 owner could watch and copy and have a solid foundation if they’re not making an all-out race engine. Michael at L&M was an outstanding resource during this process. We developed a plan, a parts list, tapped our knowledge resources, and off we went.”

While the factory 5.4- and 5.8-liter engines are renowned for their as-delivered durability, even these rugged engines are susceptible to failure when they are pushed hard. Fortunately, BJ avoided catastrophic failure when he noticed something was a little off about Christine while doing peak-power development on the VMP Gen2R TVS supercharger.

On this day, VMP Performance General Manager BJ McCarty should have played the lottery. Knowing how his 2007 Shelby GT500, Christine, should feel, he sensed an unusual vibration after an all-out dyno session. It turned out the overdrive damper was cracked and about to fail. Running it much longer might have resulted in complete destruction of the engine. (Photo Credit: VMP Performance)

Something’s Not Right

“I drove her home and noticed an imbalance that frankly I thought to be a tire. With all of the drag suspension on the car, you can feel every tiny road imperfection or tire issue,” he explained. “Anyway, the same thing occurred on the way to work and I started hearing some chirping like belt or maybe an idler bearing. I cleaned the belt, swapped some idlers out and it was still there.”

BJ’s intimate knowledge of Christine’s moods was a lifesaver — for her block. It turned out that the overdriven damper was ready to give up the ghost. He caught her just in time, which meant the stock engine could be revived before a catastrophic failure.

Fortunately the engine was all in one piece, so BJ removed and disassembled the engine. Then he sent the block and heads off to Central Florida Machine where it was dipped, returned it clean and sporting a fresh coat of black paint.

“So, we removed the harmonic balancer and bam! There it was — a crack that paralleled the keyway from end to end. It would have taken one or two more WOT hits or a hard launch and it would have all been over,” BJ confessed. “This is the best example of dodging a bullet that I’ve seen. That said, we’d just seen 850 rear-wheel horsepower on the VMP Gen2R, so Christine had done her job. The car had 65,000 miles on it! It’s one of the first ones built in June of ’06 and she hasn’t exactly been pampered.”

With the idea of creating an affordable package for others to follow, BJ set the goal of 900 rear-wheel horsepower and put together a package of parts that were up to the task, but not overkill for the budget. The centerpiece of the build is a Ford Performance Cobra Jet crankshaft, which he had machined for dual keyways. Rounding out the reciprocating assembly are Manley forged H-beam rods and flat-top pistons that raised the compression ratio from 8.4:1 to 9.7:1.

Starting Fresh

That said, Christine’s engine was about to get pampered with a lot of good stuff. BJ wanted to create a durable combination that could withstand the kind of power customers expect but could be packaged for them to replicate without commissioning an all-new engine. The foundation of this stock-block rebuild is Ford Performance’s Cobra Jet crankshaft, which a local machine shop cut for dual keyways and balanced.

First, we decided on a power goal. That would dictate our parts list. — BJ McCarty, VMP Performance

“First, we decided on a power goal. That would dictate our parts list. If we made 850 on the stock long-block, we wanted to add a set of L&M NSR cams on this build, so we were going to up the compression ratio a bit with that in mind,” he said. “We reached out to Tom Razzano at Manley Performance who spec’d a set of Manley H-Beam forged rods with ARP 2000 hardware. He also helped us pick the flat-top Manley pistons for a 9.7:1 compression ratio, up from the 8.4:1 stock ratio. It’s aggressive for pump gas, but we knew she’d always be on E85 at full tilt and also knew that the L&M cams would bring the ratio down to a manageable number.”

Next BJ installed the refreshed cylinder heads and stock camshafts atop the new short-block. Waiting in the wings, however, were a set of custom no-spring required camshafts spec’d by L&M Racing Engines and ground by Comp Cams. He added all new cam chains from Ford along with a billet crank gear from Triangle Speed Shop.

Also manageable is the assembly. VMP wanted GT500 customers to be able to have the machine work done locally and then be able to screw the engine together themselves to make the fortified engine a more affordable project that could keep supporting even more performance in the future.

Start by removing and tearing down the stock engine. BJ recommends that you take lots of photos so you’ll know where all those parts go. He also suggests inventorying and organizing all the small parts and fasteners in plastic bags labeled with a permanent marker. That way you won’t end up missing those crucial parts when you start the rebuild. Once the block is stripped down, you can deliver the block to the machine shop (and the heads too if you want to go ahead and freshen them).

Next he installed the timing cover, cam covers, and lower intake using all new Ford gaskets and seals.

Next he installed the timing cover, cam covers, and lower intake using all new Ford gaskets and seals.

With the block machined and crank balanced, mount it to an engine stand, give it a thorough bath and move it to a clean workspace. There you can use 30-weight oil to lube the cylinders before you start dropping in the crank, rods and pistons. You’ll want to get your hands on a shop manual to ensure you are assembling things correctly, but there are some good online resources for torque specs and assembly tips as well. Naturally you’ll need the right tools as well, including both a 3/8- and 1/2-inch torque wrench.

BJ rounded out the combination with his extant Dynotech exhaust and McLeod Racing RXT 1200 HD clutch (PN 6918-07HD) as well as a new MGW shifter, the latter of which was easy to install while the transmission was out of the car.

A Stout Combo

VMP 5.4 Engine Upgrades

Bearings: King Bearings

Block: Stock w/ hone and line hone by Central Florida Machine

Camshafts: L&M no-spring-required

Coil Covers: Billet Pro Shop

Crank Gear: Triangle Speed Shop

Crankshaft: Cobra Jet crank, double keyed and balanced

Exhaust: Dynatech 1 7/8-inch long-tube headers and mid-pipe

Fasteners: ARP2000 hardware, including head studs

Fuel Injectors: Injector Dynamics 1,300cc

Gaskets: Ford OE replacement

Heads: Stock w/ three-angle valve job by Central Florida Machine

Oil-Pump Gear: Triangle Speed Shop

Pistons: Manley Performance flat-top, forged, 9.7:1 compression ratio

Rods: Manley Performance H-beam

Timing Set: Ford Performance chains, guides, arms, gears, chains

If things go according to plan, as BJ’s build did, you will have an engine far better suited to support the kind of power that modern power adders — like the VMP TVS superchargers — are capable of delivering.

“While we should be able to spin it to 7,000 rpm now, we’re opting not to. Our self-imposed limit is 6,600-6,700 RPM. We specifically didn’t opt for the Manley I-beams because we were doing a semi-budget build. The I-beams would have taken the added RPM but we feel we can make our power goals with less piston speed,” he explained. To that end, we feel we can not only hold everything the VMP Gen2R makes, but feel we’re prepared to add the L&M cams and, looking forward, continue to use Christine for R&D on our future supercharger offerings.”

If this sort of combination seems like a good fit for your S197 GT500, VMP offers this same engine kit for sale on its site starting at a reasonable $2,950. The L&M NSR cams will set you back another $1,200.

To stave off potential damper failures in the future, BJ opted for one of Romac’s Pro Series, 15-percent-overdriven crank dampers (PN A0348SA-15), which turns the blower faster and carries a racetrack-legal SFI 18.1 specification.

To stave off potential damper failures in the future, BJ opted for one of Romac’s Pro Series, 15-percent-overdriven crank dampers (PN A0348SA-15), which turns the blower faster and carries a racetrack-legal SFI 18.1 specification.

“From the Ford/Manley rotating assembly to the L&M NSR cams to our VMP Gen2R TVS supercharger, we’re one-stop for parts as well as tech support,” BJ added. “Package prices will depend on your goals and from where you’re starting your build. If it’s something beyond that or they’re looking for a full build, we’ll send them to Michael and L&M for the full monty.”

For more on this package, you can visit the VMP Performance site here.

Feeding the new combo with ample E85 are a new set of ID1300 fuel injectors which will support up to 23 pounds of boost on this engine.

Removing and replacing the engine served as an opportunity for a new K-member. BJ upgraded to one of Maximum Motorsports’ stout units.

BJ swapped over the same VMP Twinjet 67mm throttle body, JLT Super Big Air cold air intake, and JLT oil separator from the previous combination to the new engine.

Rounding out the Dynatech 1 7/8-inch long-tubes is a Dynatech mid-pipe

Rounding out the Dynatech 1 7/8-inch long-tubes is a Dynatech mid-pipe.

After breaking in the new engine, BJ strapped Christine down to the VMP Dynojet chassis dyno and dialed in a new calibration. With this combination setting a new baseline, he then swapped in the aforementioned L&M NSR camshafts to see just how much a cam swap would benefit the new setup.

After breaking in the new engine, BJ strapped Christine down to the VMP Dynojet chassis dyno and dialed in a new calibration. With this combination setting a new baseline, he then swapped in the aforementioned L&M NSR camshafts to see just how much a cam swap would benefit the new setup.

With just the new short-block in place, Christine belted out 851 horsepower and 826 lb-ft of torque at the rear wheels. Swapping in the Comp-ground L&M bump sticks yielded and impressive gain of 80 horsepower but the lumpier cams did give up 29 lb-ft torque in exchange.

With just the new short-block in place, Christine belted out 851 horsepower and 826 lb-ft of torque at the rear wheels. Swapping in the Comp-ground L&M bumpsticks yielded and impressive peak-to-peak gain of 80 horsepower but the lumpier cams did give up 29 lb-ft of torque in exchange.

While you might be wondering why BJ was willing to give up some of his Shelby’s bottom-end torque by swapping in the L&M NSR cams. The answer is simple. Having 800 lb-ft of torque on tap that low in the powerband makes launching a 4,000-pound car pretty tricky. That’s why BJ was happy to give up a bit of umph down low and shift the gains higher in the powerband — a powerand that extends much higher — making the car more tractable on launch. If you have never driven one of these TVS boosted 5.4s, we can assure that this shift in powerband is likely to make this car run better at the track when BJ gets a chance to run again.

While you might be wondering why BJ was willing to give up some of his Shelby’s bottom-end torque by swapping in the L&M NSR cams. The answer is simple. Having 800 lb-ft of torque on tap that low in the powerband makes launching a 4,000-pound car pretty tricky. That’s why BJ was happy to give up a bit of grunt down low and shift the gains at a higher RPM, making the car more tractable on launch. If you have never driven one of these TVS-boosted 5.4s, we can assure that this shift in powerband is likely to make this car run better at the track when BJ gets a chance to run again.

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About the author

Steve Turner

As Executive Editor of FordNXT and Ford Muscle, Steve Turner brings decades of passion and knowledge to Power Automedia. He has covered the world of Ford performance for over 20 years. From the swan song of the Fox Mustang to the birth of the Coyote, Steve had a front-row seat.
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