it has the correct motor in it from new ,it just noisy ,from wear and tear , i bought the gto motor as looked same motor but is 5 mm short the caterham motor is to short, and the mclaren merc 722 motor is to short, ive been told the viper and the tvr 400r have the same motor, then am left with the fact, cant get hold of a tvr long shaft either ,i tried to change the pinion on it which came with the new rear axle i bought ,hence i kinked the spring on the shaft ,which made it sound a whole lot worse ,ive given up ,decided to sell the 3 vipers i have as spares or repaires ,as there all well used looked after ,but the running gear is in need of replacing ..