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.
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
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.
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.
“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.”
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
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).
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.
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
“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.
“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.