Lamborghini Miura manual indicating bigger intake valves in English size (but correct size in metric). The intake and exhaust valves in all 4 liter Lamborghini V12 remained the same throughout all models. This intake size misprint carried forward into Espada 400GT and Countach LP 400/LP 400S owners manuals as well. In 1970, Lamborghini development driver Bob Wallace created a test mule that would conform to the FIA's Appendix J racing regulations. The car was appropriately named the Miura Jota (the pronunciation of the letter 'J' in Spanish). Wallace made extensive modifications to the standard Miura chassis and engine. Weight reductions included replacing
V12 engine each piston can be smaller, lighter, and with a shorter stroke. Exhaust system tuning is also much more difficult on a crossplane V8 than a V12, so racing cars with V8 engines often use a complicated "bundle of snakes" exhaust system, or a flat-plane crankshaft which causes severe engine vibration and noise. This is not important in a race car if all-out performance is the only goal. Since cost and fuel economy are usually important even in luxury and racing cars, the V12 has been largely phased out in favor of engines with fewer cylinders. Engines are often designed around