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Turbocharged 363 Stroker Engine Build - 200-MPH Takedown
We Show You What Goes Into Building A Turbocharged 363-Inch Stroker Designed To Push An '88 5.0L LX Mustang To 200 MPH
By now, most loyal MM&FF readers have probably forgotten about our ill-fated 200-mph Mustang, and rightfully so-the project started way back in the early '90s.
Having successfully run the Silver State Classic open-road race in Nevada on a number of occasions (including an overall win), it was time to step up the performance of our '88 5.0L LX Mustang-substantially. Using a Vortech supercharger and assorted bolt-ons, including a GT-40 intake, TFS High-Port heads, and a Crane 224/232 cam, the 302 eventually pushed the little pony past 190 mph. Those were pretty impressive numbers back in the day, especially given the fact that this was a real street car. In fact, it served as the sole means of transportation for a great many years). This was no trailered show queen, or even a pseudo street car (race car with a license plate)-it was an honest-to-goodness 190-mph street Mustang.
If that wasn't enough, the car was driven to and from every event with one exception. One Silver State race saw the replacement of the B-trim Vortech with an R-trim, along with a significant increase in boost. Higher boost combined with little in the way of tuning (this was prior to the availability of now-common Dynojet chassis dynos) resulted in a molten piston chunk finding its way out past the cylinder head-yes, it was ugly.
Fast-forward to 2010, and we have decided to resurrect the old gal and prep her for life in Y2K (plus 10). Coming full circle since the famous 5.0-liter Fox, Ford has introduced a new body style, a new modular engine family, and a retro Stang with (of all things) a resurrected 5.0-liter.
With over 400 hp, the new 5.0-liter motor is a far cry from the original 302 (originally rated at 225 hp). In addition to the changes in the Mustang family, the aftermarket performance levels have continued to rise. Not long ago, a 500hp street Mustang was a pretty serious piece. Now it seems 1,000 hp is the new 500 hp.
While 1,000 hp is certainly more common (check out the dyno results of this motor for instance), the reality is that an honest 1,000 hp is all but useless on the street. Harnessing that much power is difficult, if not impossible, on street rubber. And where on public roads are you able to successfully unleash all that fury? This is especially true of a Mustang set up for top speed, as you quickly race past toss-me-in-jail speeds and venture into yank-me-from-my-car-and-pistol-whip-me speeds.
Another side of the argument against 1,000hp street or even top-speed cars-at least those looking to exceed 200 mph-is the fact that it doesn't take anywhere near that kind of power to push a Mustang into the double century. Though the Fox Mustang is not known for its aerodynamic prowess, exceeding 200 mph requires closer to 500 rwhp (around 600 flywheel horsepower). Given the myriad of combinations currently available for the 5.0-liter, eclipsing 500 rwhp is a simple matter of combining the right heads, cam, and intake with a forged short-block and almost any type of forced induction. Heck, the blower or turbo doesn't even have to work hard. We've run turbos on bone-stock 5.0-liters that exceeded 500 rwhp at around 15 psi, but this number dropped to just 8 psi with aftermarket heads, cam, and intake. Toss in additional displacement, more aggressive cam timing, and even better heads and intake, and it very well might be possible to push a Mustang past 200 mph with around 5-6 psi. For that matter, you could run the all-motor route and stick in a 408, 427, or even 460-inch stroker and get there as well. When it comes to motivation for a 200-mph Mustang, there is no shortage of engine combinations.
Those of you who have skipped ahead to the dyno results might be confused about now. Why would we dismiss the need for a 1,000hp build-up only to turn around and produce exactly that? Didn't we just say that it only takes 500 rwhp (600 flywheel) to reach 200 mph? What is the deal with all the extra power? Well, times have changed and so have our goals. Though the number of 200-mph street Mustangs is indeed rare, the simple fact that it can be done has already been proven. Rather than continue down that same "me-too" road, we decided to raise the bar and build not just a 200-mph 5.0-liter Mustang, but one that could achieve that speed in the standing mile.
Standing-mile competitions have become very popular, and for good reason. The format lends itself to impressive results without having to design a car to run flat out for 5 (in the case of Bonneville) or even 90 miles (Silver State Classic). Standing-mile competitions are a performance mix, combining both traditional quarter-mile drag racing with dry-lake or Bonneville top-speed runs. Getting a Mustang to run 200 mph is considerably easier than achieving that feat in just one mile. The horsepower requirements jump up considerably to say nothing of the traction and aerodynamics.
With our now-elevated bar, we immediately realized that just any old engine combination wasn't going to do.
Our first concern was the block, as making power is actually the easy part. Knowing this, we decided on a block from Dart Machinery. The Dart 8.2-deck block featured four-bolt splayed (steel) caps on the three center mains, with two-bolt caps being used on the outer two. Beefy 1/2-inch main bolts were employed, and the valley was machined to accept the factory hydraulic-roller guides and retainers. The Siamese cylinders measured a minimum 0.230 thick (at the maximum recommended 4.185 bore size), while the block also featured a true priority-main oiling system to ensure adequate lubrication at elevated engine speeds. To ensure proper sealing in high boost or cylinder-pressure applications, the Dart block featured a 0.625 deck surface and 1/2-inch (blind) head bolt holes.
As luck would have it, Dart supplied not only the perfect block, but the perfect short-block. Some time ago, Dart shipped one of its impressive SHP short-blocks, stuffed to the gills with all manner of forged internals. Since Dart offered the SHP short-block in a number of different configurations, we had to choose a suitable SHP candidate. Dart offered the SHP combination with the 302-based, 8.2-deck block in two different displacements. The displacement change was based on the bore size, as both the 347 and 363ci SHP short-blocks shared the same 3.40-inch stroke. The 347 utilized the smaller (more common) 4.030 bore, while the 363 stepped up to a 4.125-bore block. Dart offered both combinations with a cast-steel crank, though a 4340 forged-steel crank was an option. Regardless of the crank selected, both feature 4340 forged steel H-beam rods (I-beam rods were an option) and forged flat-top pistons. The pistons featured generous valve reliefs, deep enough (we discovered) for a 260-degree, 0.730-lift roller cam. Additional features in the SHP short-block included Hastings moly rings, Clevite rod and main bearings, and even coated cam bearings. Though not listed in the description, our short-block featured coated pistons as well. Basically the SHP short-block featured all the trick stuff you'd want if you were building one yourself. Knowing boost was in the cards, we elected to go with the 4.125-bore block, along with a forged crank, rods, and pistons.
With our short-block covered, we started in on power producers, namely the heads, cam, and induction. Early on, we decided that having extra engine speed might help us with our gearing, so we elected to run a solid-roller cam to extend the effective operating range to 7,000 rpm. The intake and heads were given the same consideration, as we were looking for a power peak slightly below 7,000 rpm, while maintaining the ability to rev that high to improve acceleration and average power production once we made the necessary shifts. Proper cam timing for our boosted stroker was provided by the Ford cam experts at Cam Research Corp. We once again relied on them for cam timing for the turbo motor. Cam Research Corp supplied what we thought was a pretty mild profile, at least in terms of duration. Taking full advantage of our high-flowing AFR 225 heads, the solid-roller cam supplied for our 363 checked in with a healthy 0.736/0.727-lift split, a 254/252 duration split, and a boost-friendly 112-degree lobe separation. Though the 254/252 duration split seemed tame, the results were nothing short of amazing, both normally aspirated and turbocharged. The Cam Research Corp cam was combined with roller lifters, a double-roller timing chain, and hardened pushrods all from Comp Cams. The final touch of valvetrain hardware was a set of 1.7-ratio gold roller rockers.
Given the displacement and use of flat-top pistons, the static compression ratio was a tad high for a boosted application with your typical 60cc combustion chambers. Though we've successfully run turbo motors with 11.0:1 compression (or higher), this was not a dedicated race motor-it would see plenty of street driving in addition to the standing-mile competition. For this reason, we elected to run a set of AFR 225 aluminum heads that offered not only impressive flow numbers (325/258 cfm at 0.700 lift), but also a great many other features. The AFR 225 heads featured lightweight 8mm (2.08/1.60) valves to improve effective rpm, ultra-thick (0.750-inch) deck surfaces to minimize distortion and improve sealing under high-boost applications and a raised exhaust port to maximize exhaust flow. Another nice feature of the AFR 225 heads we selected was the 72cc combustion chamber size, which brought the static compression ratio down to a more streetable 10.0:1. The AFR 225 heads were set up with a valvespring package suitable for our 0.736-lift roller cam.
We then turned our attention to the induction system. Running this motor previously with a Holley 950 HP and Funnel Web intake, we were tempted to blow through this carbureted combination, but elected to go the EFI route instead. Concerned with power production higher in the rev range, we decided to employ the effective Trick Flow Specialties Box R upper and lower intake manifold. The Box R upper intake was designed to accept a 90mm throttle body from Accufab. The Accufab throttle body offered both an impressive visual statement as well as tremendous flow. Compared to the 75mm Renegade throttle body tested in normally aspirated trim, the 90mm throttle body improved the power output by 17 hp.
On the normally aspirated combination, we retained the factory fuel rails and ran a set of 36-lb/hr injectors. The turbo motor was run with 75-pounders (from Holley) and high-flow, aluminum fuel rails from Vortech. ProComp Motorsports supplied the neutral damper (the SHP short-block is internally balanced), front cover, and fabricated valve covers. Additional components included a Milodon oiling system, Hooker 1 3/4-inch Super Comp headers, and an MSD billet distributor. Run in anger, the normally aspirated 363 stroker produced peak power numbers of 519 hp at 6,600 rpm and 469 lb-ft at 5,000 rpm. Torque production from the Dart SHP motor exceeded 450 lb-ft from 4,300 rpm to 5,800. Even down at 3,000 rpm, the 363 still produced nearly 400 lb-ft of torque, so turbo spool up should be more than adequate, even with a sizable (80mm-plus) single turbo.
Speaking of turbo, we installed a single-turbo kit from HP Performance. The kit included the necessary tubular exhaust manifolds, crossover tube, and wastegate flange. It also featured a thermal barrier coating to maximize heat energy to the turbo, as well as an efficient air-to-air intercooler to maximize heat rejection. Initially, we hoped to run a 76mm Precision turbo, but we later stepped up to a larger 80mm unit from Comp Turbo to reach the desired 1,000 hp. The 76mm from Precision will likely be more than adequate for our 200-mph adventure, but we wanted a big number on the engine dyno (remember, 1,000 hp is the new 500 hp).
Turbo Smart provided a 45mm wastegate to help control the boost pressure supplied, along with one of its Race Port blow off valves to eliminate any surge when we lifted of the throttle at high rpm.
After tuning with the FAST management system, the turbo motor eventually responded with peak numbers of 1,004 hp at 6,300 rpm and 890 lb-ft at 5,100 rpm. Despite the sizable turbo, boost registered over 14 psi at 3,500 rpm, and climbed to a peak of just over 18 psi before falling off slightly to 17.3 psi at the power peak.
There was a little more power to be had from this turbo combination at higher boost levels, but we officially eclipsed the 1,000hp mark in a mild state of tune, and we're now anxious for the install. Check out upcoming issues for that and a few drivetrain upgrades before we head out for the big test. We promise it won't take a couple of years this time!