Michael Johnson
Technical Editor
January 1, 1999

Step By Step

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Can you say, “More than 500 hp with a stock cam?” We knew you could—with an Incon twin turbo kit, that is. Our subject made 525 hp and 591 lb-ft of torque on 13 pounds of boost—with a stock cam, box-stock GT-40X heads, and GT-40 intake featuring a ported lower! These numbers came courtesy of Dyno Performance Engineering and its mobile Dynojet. DPE is located in West Palm Beach, Florida, and makes the rounds at Hot Rod Power Festivals and assorted Ford racing events.
Jay Meagher of LaMotta Performance installs the turbo with exhaust manifold, without using a gasket. These manifolds are surfaced so there’s no need for gaskets. If you do install gaskets, you will have an exhaust leak straight away. Meagher holds the manifold while he starts the two outside bolts.
Some areas are harder to get into than others. Though it is easier to change and install plugs with the engine out, it is possible to change them with the engine in. Just make sure the engine is stone-cold before doing so. Incon recommends three tools from Snap-On to help in the plug changing process: a spark plug socket (PN S9706KFUA); a 3/8-inch, 12-point socket (PN TMU121); and a 3/8-inch, 12-point wrench (PN XDH1214A). Plan on taking your time with this task.
Incon supplies this oil-pressure sender adapter to provide oil to the turbo-chargers for proper lubrication. The oil runs through the turbos and back into the oil pan.
The turbos are water-cooled, which means you must also tap into the cooling system of the engine. Meagher is attaching the supplied coolant lines from the thermostat housing. You must drill (19/32-inch) and tap a 3/8-inch NPT hole in either the thermostat housing or the intake water passage just behind the thermostat housing to provide a water passage to the turbos.
Here’s a better look at the oil and coolant lines as they pertain to the turbos. The hose entering the oil pan is the oil-return line; the hose entering the side of the block is the coolant-return line. The coolant-return line attaches where the drain plug was located. Remember to use thread sealer on all fittings involving coolant-line attaching points.
Before we drop in the engine we need to install the distributor, plugs, and Incon- supplied Taylor plug wires. Incon’s instructions lay out the routing of the plug wires for you, and it’s best if you go ahead and install them with the engine out of the car. This is your last chance to make sure all oil and coolant lines are properly attached. Better to find them loose now before you get the engine back in the car and find a leak.
Incon supplies extended spark plug wires which route around the manifolds and turbos. As you can see in this diagram, No. 6 loops underneath the manifolds and No. 8 runs along the lower intake, so you should go ahead and install the wires before dropping the engine in.
This is where the provision for the passenger-side turbo is required. Use a cutting wheel to cut out the piece of the framerail and weld in the new piece. This modification keeps most people from getting the twin-turbo kit. If you don’t know how to weld, have a chassis shop, certified welder, or body shop complete this step for you.
The driver-side motor-mount bracket must be notched (arrow) to clear the oil-return line. This is not necessary if you use the supplied spacer. This is a critical part of the installation. You definitely want the oil lines free and clear of obstruction.
These spacers go between the motor mount and the motor-mount bracket on the K-frame, providing extra clearance for the turbos on each side.
When reinstalling the engine, make sure there are no wires or lines in the way holding it up. With the added width of the engine because of the turbos, space is a little more cramped.
Once everything is bolted into place, reattach the fuel lines and accessories.
This is why you need to either notch the motor-mount bracket or use the supplied spacer for the driver side. Notice the location of the oil-return line.
Space is also especially hard to come by on the passenger side, even with the Incon clearance plate in place.
These air filters are provided with brackets that mount to each side’s frame-rail. Notice how Meagher clearanced the inner-fender splash shield for the supplied air-intake hoses.
The intercooler is attached to the air filter brackets just behind the radiator. The factory air dam is then attached to the intercooler. The intercooler cools air exiting the turbos before it enters the engine, improving air density and reducing the chances of detonation.
Check out the mac-daddy clamps Incon includes in the kit. This hose is used to return air from the turbo back into the intercooler. The air moves through the intercooler, up through the air-intake tract, and into the engine.
This hose brings cool air from the intercooler up to the Incon air-intake tube (which includes an 80mm mass air meter from Pro-M).
Here’s a closer look at the coolant T placed in the thermostat housing. You can either drill and tap the T in this location or into the water passage in the intake just behind the thermostat housing.
This supplied shield is used to protect the brake fluid within the master cylinder from boiling, making your brakes non-existent. Note the relocation of the speedometer and clutch cables within this bracket, as well as the supplied bracket for relocating the dipstick tube.
Incon supplies this intake tube with an integral Pro-M 80mm mass air meter.
Install the intake and new radiator hoses. Fill the radiator. Double-check everything for leaks, especially fuel lines, before you start the engine.
Now we’re ready to rock. The car idles like a stocker, hammers the dyno rollers to the tune of 500-plus horsepower at the rear wheels, and gets 20 mpg. Those not in the know will never suspect what you have under the hood until you mash the go pedal and rip the paint right off their car. Here, F-body, Corvette, Grand National—I’ve got two surprises for you.
This diagram shows the placement of the supplied clearance plate and motor mount spacers. Both are vital points of the twin- turbo install.
Air enters the turbos through the twin filters, then…
…comes back out and down through the intercooler and into the engine via the Incon air intake tube. Air is monitored through a Pro-M 80mm mass air meter.

For most of us, when we think of a street turbo car, we think about the Mustang SVO, the Buick Grand National, and the occasional Chrysler front-driver. Sure, all were pretty quick for being totally stock, especially the Buick, but turbo lag always reared its ugly head. When one is used to mashing the pedal and feeling the instant rush of horsepower, a turbo car feels decidedly different. With a torqueless four-banger like the SVO, you may have to wait a second or two until the turbo spools up when you put the pedal to the floor at lower rpm. This has been dubbed turbo lag, but the combination is really to blame, and this reputation made turbos a less marketable power adder.

Today, because of improved packaging and availability, turbos are making a comeback from the turbo-lag misnomer, as a torquey 5.0 with a turbo can provide immediate and constant gratification. Turbo pioneers such as Gene Deputy, Racin’ Jason, Mike Ragusa, and Hurley Blakeney were making obscene power back in the early to mid-’90s, and are largely responsible for the resurgence we’re enjoying right now. Turbos are everywhere, especially on the dragstrip. On the street, however, they’re a little more controversial. They still make obscene power, but the initial installation and spark plug maintenance is what scares people away from most street-oriented, twin-turbo kits.

Granted, a single-turbo kit takes up less space than a pair of twins. And in order to install some twins, you may have to make a provision for the passenger-side turbo and notch the driver-side motor mount. Still, there’s noticeably less turbo lag through the use of two small turbos. This is why most factory turbo-powered cars of the recent past (Nissan 300ZX, Mazda RX7, Toyota Supra, and so on) have had twin turbos.

To see what a modern turbo kit installation entails, we paid a visit to LaMotta Performance in Longwood, Florida, to observe an Incon twin-turbo installation. Owner Jake LaMotta is a longtime supporter of Incon Systems, and he even drives his 5.0-equipped, 10-second, twin-turbo Mustang SVO every day.

Incon’s twin-turbo kit comes with everything needed for installation: an intercooler, a 255-lph fuel pump, 30 lb/hr injectors, and a Pro-M 80mm mass air meter. The kit even comes with new Taylor spark plug wires featuring heat insulation to protect the wires. Incon’s ball-bearing turbos are water-cooled to fight against bearing failures and to maintain an acceptable level of underhood temperatures. Incon’s focus is on street kits that make massive power for the daily driven Mustang, while remaining docile enough for grocery trips with the significant other. The Incon twin-turbo kit is the only one on the market featuring a California Air Resources Board Executive Order number, which means the kit is 50-state emissions legal.

For our installation the engine was out of the car, which is the preferred method of installation. The boost-greedy owner lunched a head gasket at the track, so the motor was removed for a gasket R&R. You’ll have to pull the engine to perform the framerail modification anyway, so you might as well put everything together with the engine out; it’s much easier that way. Jay Meagher, who handled the bulk of this installation, says it usually takes two days to completely install the kit, so unless you are a deft mechanic you should seriously consider a professional installation.