1991 Firebird Formula 350 WS6 Convertible Firehawk

Firehawk decal


This 1991 Firebird Formula 350 WS6 Convertible is believed to be 1 of 1. I purchased this Firebird from an estate which had one of the largest Pontiac collections in the country. I was told the collection consisted of over 1000 cars. Unfortunately, the previous owner passed and thus the selling off of the collection became the responsibility of the wife and son, which had very little knowledge of the vehicles and documentation. I was told that most of the collection went to a museum.

Although I didn’t get much in the form of documentation, the serial number is that of a Formula 350, and according to the RPO codes, the car is equipped with many of the preferred performance options. This is indeed a Formula 350 WS6 handling package optioned car. The car has front and rear disc brakes, RPO code J65. The fronts and rears are slotted and drilled, the fronts are 13″ diameters. The chassis has an abundance of braces, a must for F-body convertibles. The car drives as solid as any fixed roofed F-body I have ever driven. The polished aluminum valve covers are engraved with the words ” Pontiac Performance Motorsports Division” I tried my best to investigate this further and have come up with very little information, although google did find some information on a group of General Motors, Pontiac engineers that worked on a special project which included several Firebirds.

The exhaust consist of true dual stainless attached to the dual cats. The intake runners are the SLP’s siamese. There’s also a alteration modification information plaque in the engine bay, with the formulas VIN number. For what it’s worth, from some of the very limited documentation I got with the car, it does show that this car was originally titled in Detroit Michigan. Back in 1991 I purchased a Pontiac GTA which was ordered for one of the executives within the Pontiac division, and it also was originally titled in Detroit.

The Firehawk decal kit came with the car, but were not installed. I took the liberty of installing them as they finish the looks of this car perfectly.

Regardless of the documentation, this is a very rare bird with many cool performance goodies. At car shows, it’s definitely a crowd pleaser.

























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1988 Callaway Corvette Convertible (1 of 65)

Callaway logo

1988 Callaway Corvette Convertible RPO B2K
The special edition Callaway Twin Turbo Corvette was available from 1987 to 1991 as Regular Production Option (RPO) B2K and could be ordered from select dealers in the US. Corvette orders with the B2K option selected were shipped to Callaway Cars in Old Lyme, Connecticut, for the Twin Turbo conversion directly from the Bowling Green Kentucky assembly plant.
While the final production exceeded 500 Corvettes, the total that were ordered through the Bowling Green plant was lower due to a few factors. These factors included many dealers sent cars already in the process of delivery to their stores, or may have been on their lot and were used to “prime the system.
105 cars were ordered with RPO B2K, while Callaway records show 125 cars constructed.
Bowling Green records showed 50 coupes and 55 convertibles made while Callaway records showed 60 coupes and 65 convertibles. 1988 also saw the official release of the automatic transmission – 10 coupes and 16 convertibles were equipped this way. In 1988, Corvettes saw 17-inch wheels become available. Callaway Corvettes for that year (and subsequent years) wore handsome, silver 17” Dymags that utilized the base Corvette locking center cap. The Dymag wheels were manufactured in Europe and were made of super light weight Magnesium alloy.

For 1988, Callaway increased the stock performance of the Twin Turbo Corvette to yield 382 hp (285 kW) and 562 lb•ft (762 N•m) of torque. That year, 125 Callaway Twin Turbo Corvettes were built with 105 ordered with the RPO B2K option.
In 1988 owning a sports car with 382 hp and 562 lb.ft of torque, was unheard of, which put the Callaway Twin Turbo Corvette in the Super Car category. Of course although this was incredible power, it wasn’t quite enough for me. Knowing the ins and outs of these cars, I decided to modify my 88 slightly from factory. The first performance part ordered, was directly from Callaway. Since one known weakness in the system was the air intake flow. Callaway had designed the “Wonder Bar” that did away with the factory stock design which restricted air flow from the air filter. Next came an aftermarket intake, which consisted of (SLP Siamese runners, ACCEL Big Mouth Intake and modified ported plenum to match. This did away with the factory TPI runner and intake system which was a major source of restriction, and limited rpm power to about 5000 rpms. Larger fuel injectors and roller rockers topped off the engine combination, which allowed the beast to now make power well above 6200 rpms. For an exhaust, I fabricated a true dual 3″ stainless system. The hp now is well above 700, while torque is in excess of 800 ft. lbs.
If you ever wanted to experience the feeling of being launched off a navy carrier, this car will accomplish that.

DCP_0781DCP_0783DCP_0784DCP_0782DCP_0774DCP_0778DCP_0779DCP_0789DCP_0785DCP_0768DCP_0771DCP_0770DCP_077288 callaway engineDCP_0769DCP_0773DCP_0767DCP_3621DCP_3642DCP_3964DCP_3960ported runnersCrane rockerssiemese side view12

1991 Callaway Corvette Twin Turbo Convertible (1 of 6)

1991 Callaway Corvette Twin Turbo Convertible Driver Side Distanced

1991 Callaway Corvette Twin Turbo Aerobody RPO B2K

Callaway logo

This is 1 of 6 ever produced. This car was originally built through the G.M. rpo B2K option order, for the manufacturer of Dymag Wheels. Dymag Wheels were offered on the 87-early 91 Callaway Twin Turbo  cars. Wheels were made of magnesium, although in the last batch of production, Callaway switched to the OZ racing line which were applied on the ultra rare Callaway Twin Turbo Speedsters. Callaway Corvettes with the Aerobody package were aerodynamically capable of hitting 190+ mph. Hitting these speeds in a production vehicle was unheard of at the time. Also unheard of was the price tag of this car, as it had a window sticker of $121k, making it the most expensive GM car of the day. Again, we’re talking about 1991 money. In today’s money, this amount would equate to $180k+. Because of the break up between Callaway and the owner of Dymag, this car was sold to its European owner, the famous Phillipe Charriol, a well-known Swiss Jewelry/Watch designer and manufacturer who was also a very well respected race car driver in European circles.


1991 Callaway Corvette Twin Turbo Engine Performance Specs:

  • 403 hp (301 kW) and 582 lb ft (789 N x M)
  • Special Engine Prep and Components:
  • Splayed 4 bolt mains
  • Forced Gas Nitrided Crankshaft, 60Rc Journal Hardness
  • Proprietary Mahle Forged Pistons with 7.5:1 compression; Plasma Moly Ring Package
  • Dry sump pump for turbo oil scavenge and polished air inlet castings
  • Balance and Blueprint Operations Include:
  • Magnaflux Block and Crank Assembly, crankshaft journals cross-drilled and micropolished
  • Aluminum cylinder heads decked; line bore main bearing caps and block; decks squared to crank centerline; all galleries cleaned and replugged; valve springs shimmed for equal pressure, and all threads chased.

Production for 1991:

There were 62 ordered in this last year of Twin Turbo production. In total, 492 B2K Callaway Twin Turbo Corvettes were ordered through the normal sales channels. Of these, less than half were convertibles and of those, 6 were ordered through GM with the new Aerobody.

The most famous of the Callaway Twin Turbo was the 1988 prototype named “The Sledgehammer”. The Callaway Sledgehammer Corvette held the World Street Legal speed record of 254.76 mph.

The special edition Callaway Twin Turbo Corvette was available from 1987 to 1991 as Regular Production Option (RPO) B2K and could be ordered from select dealers in the U.S.. Corvette orders with the B2K option selected were shipped to Callaway Cars in Old Lyme, Connecticut, for the Twin Turbo conversion directly from the Bowling Green assembly plant.

Once converted and tested, the Callaway Corvettes were then shipped to their ordering dealers for final delivery to their respective owners. Dealer repairs of the Callaway Twin Turbo Corvettes were covered by the standard GM 12 mo./12,000 mile warranty, with Callaway Cars, Inc. reimbursing dealers for the time and materials on repairs to the added components. This was the only time when GM has allowed a factory order able non-GM performance enhancement on the Corvette.

From 1987-1991, a total of 497 (B2K) Callaway Twin Turbo Corvettes were ordered through the normal sales channels, making the Callaway Twin Turbo Corvettes some of the most collectible and rare Corvettes in history.