Which parts would be advised NOT to solid mount or poly bush on a cosworth? I have a stripped out 2wd sapphire with an awful rattle from the transmission when off throttle between 3k and 2k revs, it sounds like the prop is smashing my gearbox to bits but it's instantly gone when on throttle. So basically where would you draw the line with poly bush, what should be left rubber and what's best solid mounted?