were made of much thinner material. The rear bumper lacked an internal supporting subframe and was simply fastened to the bodywork sheetmetal. Other weight-saving measures included removal of cooling fans, holes drilled in many internal panels and frames, plexiglass side and rear windows, thin fiberglass floor panels, and magnesium-framed seats. A 275 GTB/C fully equipped with fluids, spare tyre and tool kit weighs . In race trim without spare and tool kit, it can weigh less than , a savings of over compared to the alloy bodied road cars. Similar to the four 'Competizione Speciales', the 275 GTB/C was powered by a Tipo 213 V12 tuned to 250 LM specification with a special crankshaft, piston, camshaft connecting rods and sodium-filled Nimonic valves. Many engine castings were made from the lightweight magnesium alloy Elektron. Due to an apparent clerical error, Ferrari did not report to the FIA that the production 275 GTB had a six carburetor option, so only a three carburetor engine could be homologated. In order to make up the loss of power from using only three carburetors, Weber constructed the 40 DF13 carburetor. These replaced the six Weber 38 DCN carburetors used on the 250 LM and were unique to the 275 GTB/C. A dry sump lubrication system was also added, allowing the engine to sit lower in the chassis.The Tipo 213 engine in this competition specification produced 275- at 7500 rpm. The 275 GTB/C did not use the torque tube driveshaft configuration introduced with the 275 GTB series II, instead using a series I-style open driveshaft which made clutch changes easier during endurance races.The clutch itself was strengthened for the added stresses of racing. The transaxle was a similar design to the road version, but used a lightweight magnesium case, close ratio gears, a strengthened ZF limited slip differential and needle bearings (instead of plain bearings) between the gears and the main shaft. The 275 GTB/C was fitted with specially-made Borrani wire wheels, sized 7" x 15" in front and 7.5" x 15" in the rear. These wheels were shod with Dunlop's latest "M series" racing tyres. It was this combination that would prove to be the weak spot of the 275 GTB/C; the tyres had so much grip that they could overstress and break the spokes on the wheels. This resulted in several crashes during competition. After the 275 GTB/C, no competition Ferrari would be fitted