Dyno run today on 1989 3.4 liter Mondial t

% loss varies with the configuration of the driveline. A 308/328 that uses drop gears, always drives thru a set of gears in the trans and the ring and pinion is about 17-18%. 348/355s do about the same. 360s a little better at 15-16%. A front engine car with manual trans that locks the input/output shafts like a US car would be about 15%. Autos with non'lock torque converts (like an old US car) would be high, I'd think Michaels 25% is about right.