308 GTB s/n 20537 started life as a European model dry–sump, fiberglass 308 GTB. In late 1989 this lightweight 308 GTB was purchased by Michael Sheehan for conversion into a 288–bodied in–line engine–powered 308 Ferrari IMSA GTU car.

 

The original fiberglass body was removed and replaced with a light weight carbon fiber composite 288 GTO body with the modifications needed for racing in the IMSA GTU series.

 

The new, lightweight nose, tail, and the complete front and rear spoiler sections are all removable for instant access during racing. The chassis was heavily modified in front of the front firewall and behind the rear firewall for racing purposes. A modern state–of–the–art fully adjustable suspension was fitted and the engine was heavily modified for endurance racing with light weight crank, Crower connecting rods, ultra light weight pistons, and a full titanium valve train. An all–new slide–valve intake manifold and injection system was fabricated and installed. Dyno test gave 345 hp, then competitive for the IMSA series.

 

The engine was turned in line, a modern Motec engine management system was fitted, and a Hewland gearbox replaced the Ferrari unit.

 

The car was completed in 1992 but before it could be raced IMSA changed the rules allowing the 2–valve 3.0 liter to be replaced with a 4–valve 2.8 liter engine and so a new engine program was started to build a 2.8–liter 308 4–valve engine with a slight weight penalty added to the car.

 

Unfortunately, before the car could be raced IMSA instituted a 5–year obsolescence rule, meaning that any body design that had been out of production more than 5 years was no longer eligible to race, and so 308 GTB s/n 20537 was instantly obsolete.

 

Our 308 GTB sat until 1999, when the decision was made to try and homologate the former IMSA GTU car as an SCCA GT2 car. Previous to 1999 the Ferrari 308s had been allowed to race in SCCA GT2, but only with the original sidewinder engine layout and the original gearbox.

As per the SCCA Rulebook 2002, p. 46 in the GT specifications, paragraph 11, “any readily available transmission may be used as long as it doesn't have more than 5 forward speeds.”

Additionally, as per p. 47, paragraph 15, “transverse engines may be rotated for axle or CV joint alignment.” So the engine can also be rotated.

 

In August 2000 the SCCA accepted the Ferrari 308/288 GTO for racing, with the engine mounted in-line and with a Hewland gearbox, but the engine had to be converted from injection to carburetion and the IMSA legal 12" wide rear wheels had to be converted to an SCCA legal width of only 10".

 

The engine was removed, rebuilt and new cams compatible with carburetors were installed. New–old– stock intake manifolds and carburetors were purchased, modified and installed by late 2000 in preparation for the 2001 season.

 

In late 2000 the SCCA announced that all GT–2 cars would be allowed to use fuel injection for the 2002 season, but — not the slide–valve injection as already existed and tested. The SCCA would allow only butterfly injection and only with a 40 MM restrictor, a much smaller restrictor than used in the IMSA series. Off came the carburetors and on to the shelf they went, occupying space next to the slide–valve fuel injection.

 

It was now time to purchase an all new butterfly injection system, machine and modify as needed, fit and prepare, and back to the dyno went our 308 engine. Needless to say, the restrictors killed the top end horse power, and while torque remained good, top end horse power fell from 335 to 305 hp, a hopeless drop in horsepower for racing.

 

As 308 GTB s/n 20537 was prepared for its first test, it was time to contact the SCCA and clarify if there were any other problem areas needing to be addressed before the car could race. Per the SCCA Rulebook, 2002, p. 27, GT Specs, subsection C, paragraph 4, “the fuel cell shall be located in approximately the same location as in the original vehicle.” “it shall not be located in the protected area of the driver/passenger compartment unless specifically authorized in the GTCS.”

 

Defying any logic, the SCCA decided that the fuel cells could not be located as required by the SCCA's own rulebook nor as had been homologated by both IMSA and the FIA but instead should be mounted in the front of the car, an interesting decision by a racing body claiming an emphasis on safety.

 

Another lobbying campaign began and in July of 2002 the SCCA approved the fuel cells in their current locations, as had been approved by the FIA in 1985 and IMSA in 1990.

 

It was far too late to take a run at the 2002 National Title for the Southern California region as the 2002 national series was effectively over and so, while 308 GTB s/n 20537 was finally completed and ready to be raced, it will not be raced until sometime in 2003.

 

Stay tuned!