Up For Sale for the first time in many years is an extremely rare and unique C4 model Corvette. This is a documented, authentic 1988 Callaway Twin Turbo Corvette, built with the General Motors RPO B2K Option. This car was production number 120 of only 124 cars produced for the 1988 model year. It is one of 25 Callaway Corvettes which featured the heavy-duty Callaway automatic transmission that year. The automatic was an enhanced Turbo 400 automatic transmission with a Laycock overdrive. Fifteen of the automatics were convertibles. The automatic transmission alone was an additional $5,500 option.
Originally sold through Denny Gasper Chevrolet in Canton, South Dakota, this Callaway was sold to Gary Marshik, CEO of Fastek Products on November 18th, 1988. The car was transferred to his personal name on October 8th, 1997. The car was then purchased from Gary on September 12th, 2003 who is now the second owner and is still to this day up until his passing and the family has decided to sell the vehicle.
The car has 8,552 actual miles.
The exterior finish is called Bright Red with the original Saddle leather interior and a Saddle vinyl convertible soft top which is original and in excellent condition. Power is provided by the twin-turbocharged 5.7-liter V8 engine paired with the Tremec automatic transmission. Rated at 382 horsepower and 562 pound-feet of torque. Callaway Twin Turbo factory equipment includes the engine conversion under the RPO B2K Option, and SEO Z5G Equipment which incorporated the J55 big brake system, long air dam, power steering cooler, sport muffler system, electronic climate controlled air conditioning, dual power adjustable sport leather bucket seats, electric windows and door locks, and dual power heated mirrors.
The B2K Callaway package included an analog boost gauge displaying manifold pressure in inches of mercury. The remainder of dashboard gauges consists of and electronic digital display and features a large tachometer and speedometer with redundant numerical displays in each. A driver information center has a multi-function display for oil pressure, coolant and oil temperature, volts, fuel economy, fuel level, and more.
Mileage is accurately displayed on the analog odometer. Callaway specific emblems remain in place above the radio, at the center of the steering wheel, and includes the fuel requirement on the left side, (93 octane premium), near the headlamp switch. The car build sequence plaque is properly affixed on the cup holder lid which lists the car as 120 of 124 built for the 1988 model year.
Regular Production Option B2K signified something exceptionally unique for Corvette. It was the first and only time an engine option was available on the car from an outside company, and was installed off-site, with cars drop-shipped on General Motors carriers to Callaway Cars in Old Lyme, Connecticut, where they converted and shipped to the selling dealers. 510 Callaway Twin Turbo Corvettes were built between 1987 through 1991.
1988 Callaway Twin Turbo Corvettes featured dual Roto Master turbochargers compressing inlet air gathered from the Callaway cold air box and channeled through the boxed frame rail crossmember, to the intercoolers. Pressurized air passes through the twin heat exchangers, then fed through the “Ram’s Horn” which houses two additional Bosch fuel injectors driven by the Callaway MicroFueler fuel enrichment controller. They added fuel under boost. The factory Tuned Port Injection upper manifolding was finished in black wrinkle finish. Under-hood ducting channels cooling air to the intercooler in a clever fashion. This vehicle also retains the proper oval exhaust tips, as added by Callaway to the factory sport mufflers.
Ultra-lightweight Callaway 17” Dynamag Wheels are 9.5” x17.0” wide. These wheels retain their proper finish with proper Corvette center caps and locking lug bolts. Key is included. Tires are 275-40ZR17, front and rear.
Callaway Authenticity Documentation with this car includes the original owners manual and factory cassette tape with original Callaway operating manuals, period original magazine article and original sales brochure, original window sticker and build sheet, original addendum price from Callaway on the cost of the conversion, owner history and title history, Clean CarFax Vehicle History Report, two sets of original keys, recent service receipts where this vehicle went through an extensive service to get the car up in working order including fluids changed, radiator removed, cleaned, and installed, all new air conditioning components, headlight gears replaced, new spark plugs and plug wires, new alternator, fuel system drained and cleaned, and the list goes on. Over $3,000 just spent on the car and the mechanic is available to speak with regarding anything mechanical on this Corvette. This Corvette has also been driven over 1,000 miles in the past six months without any issues.
This Callaway also has the Wonderbar Airflow Upgrade and the 100+ Horsepower Twin Turbo Airflow Retrofit Upgraded Package which is documented in a letter put together into a nice presentation package all included with the sale of this vehicle.

VIN # 1G1YY3182J5122292
Sequence No.
1988120 C4B2K

Original Delivery Date
11/18/1988

The original list price of the Corvette alone was: $38,786.00
The Callaway Conversion Package was: $26,045.00
The Additional 100+ Conversion was $10,000.00
The original MSRP on this Callaway was: $74,831.00
Top Speed Of over 190 Miles Per Hour

THE HEART OF THE CALLAWAY L98 ENGINE:
The block used is from the standard L98 engine. It is cleaned and visually inspected for defects and then a process called Magnafluxing is used to highlight invisible flaws. For additional strength, the block is machined to accept splayed 4-bolt main bearing caps. The main journals are line-honed for straightness. Then the cylinder bores are finished to align them with the crank centerline and to remove any taper or out-of-roundness that might exist. If necessary, the block itself is decked to correct height and alignment.
A Chevrolet Special Products race crank is used in the Twin Turbo. Forged from 1053 steel, it comes with Tuftrided journals. This hardens the journals to reduce wear. After an inspection for straightness, the crank’s main journals are cross-drilled for improved oiling of both the main and rod bearing surfaces. Finally, all the journals are micropolished to optimize oiling. Mounting the race crank in the L98 block requires the use of a special adapter for the rear main seal. This adapter is machined out solid billet 6061 T6 aluminum on our numerically-controlled milling centers and then anodized for corrosion resistance.
The turbo engine undergoes higher duty cycle loading than the standard engine, so more oil volume is required to maintain a proper lubricating film at the bearing surface. A high output Melling M55HV unit is used to increase oil pressure at all engine rpm’s, with a maximum of 80 psi.
Only Mobil 1 Formula 15W-50 motor oil is used in the turbo engine, because it offers superior lubrication at all temperatures and loads. To moderate heat build-up in the oil system a separate air-to-oil cooler is installed in the nose of the car.
The connecting rods used in the Twin Turbo engine come from the same forging as LT-1 “pink” rods. Each rod is visually checked and Magnafluxed. The pin bores and bearing journals are checked for size and roundness, and honed if necessary. The rods are then weighed and matched.
To lower the compression ratio to 7.5:1, pistons of our own design are installed. The pistons are manufactured by Cosworth or Mahle, both major suppliers to Formula 1 and Indycar engine builders. For optimum sealing, plasma moly race rings are standard.
In order to meet emissions standards, the camshaft and cylinder heads remain stock. However, the standard intake valves and all the valve springs are upgraded. If necessary, the cylinder heads are decked or guarantee proper flatness.
Maintaining fuel supply to the engine during high output operation is extremely important. To meet our requirements; a Bosch pump with twice the normal capacity is used. Proper fuel pressure is maintained by a manifold pressure-biased regulator built into the fuel return line.
The right turbocharger configuration is a prerequisite for producing a reliable and drivable turbocharged engine. Correct sizing can fill in low-end torque, enhancing throttle response and drivability. Callaway tested over a half dozen turbocharger configurations on the dyno before selecting Rotomaster turbos for 1988. They generate nearly 40 extra horsepower versus the previous year without sacrificing low-end response. These turbochargers have liquid-cooled bearings to enhance reliability and long life. Coolant is drawn off the block and circulated through each turbo center section. From there it returns to the hot side of the radiator. This means turbo cooling functions within its own subsystem, reducing heat load within the engine. Each Rotomaster turbo features a compact integral wastegate cast into the NiResist turbine housing to properly control boost pressure.
The turbochargers are mounted low on each side of the engine to keep them away from heat susceptible areas high in the engine compartment. This location dictates installation of a turbo oil sump tank evacuated by a Callaway-designed gerotor pump. This prevents lubricating oil from backing up and damaging the turbochargers. The oil is then returned to the stock oil pan. The pump is integrated into a new accessory drive belt tensioner. Intake air is heated during the pressurization, so air-to-air intercooling is used to control charge-air temperature and increase its density. This results in more power and delays the onset of detonation. Aircraft quality air-to-air intercooler cores are used on our system. Airflow is routed through wire reinforced silicone rubber-tubing 2” steel piping, and polished aluminum castings. Parts subject to stress are joined by Nomex-reinforced silicone hoses.
Maintaining the correct air/fuel ratio is critical, especially when it’s in boost. The fuel curve in the GM electronics is adjusted to inject more fuel at high output levels, but primarily fuel enrichment is provided by our Microfueler II Fuel Enrichment System. This discrete fuel injection system controls a pair of Bosch fuel injectors mounted in the intake air stream. The computerized system fires the injectors at rates preprogrammed to maintain the right air/fuel ratio.
Both the GM electronic engine controls and our own fuel enrichment computer are tuned on the dyno for best power, final electronic tuning takes place in the car. This melding of human sensitivity with extensive dynamometer testing makes the Twin Turbo Corvette an exceptionally drivable automobile of impressive power.
The exhaust system has been refined to take advantage of the additional power potential of the engine. This free flowing system reduces back pressure in the exhaust tract, allowing the engine to breathe better. The combination of the new exhaust and turbos results in a 17% increase in peak torque and an 11% increase in peak horsepower versus the 1987 Twin Turbo.

Some of the standard features include anti-lock brake system, rack and pinion power steering, tinted glass, map lights, leather wrapped tilt/telescopic steering wheel, electronic speed control with resume, limited slip differential, full perimeter body side moldings, fog lights, power seats, carpeted floor mats, illuminated visor mirror, all power equipment, and the list goes on.
This car did get the optional Z52 Sport Handling Package, electronic a/c, power heated outside mirrors, Delco-Bose Music System with a cassette player, and Illuminated LH visor mirror.

The overall condition of this Callaway Corvette is very good showing its original paint and interior and nice presentable condition. Minimal wear on the car and it does not need things like weatherstripping or any paint work as many may need. The glass is all in great shape and the convertible soft top is in “like new” condition with an excellent rear plastic window as it came with from the factory. The car runs and performs very well and is impressive to drive as the car has 482 HP!

This is an opportunity to own a very unique and rare Corvette as these Callaway Corvettes are a good investment grade vehicle.

First Time Offered For Sale Since 2003!