I was accelerating hard in my 66 from 50kmh to 100kmh and experienced quite a bit of vibration at about 80-90kmh when foot to the floor. Backed off and the vibration stopped - it feels fine lower revs but what would the cause be? Probably need to balance the tail shaft.
Does anyone have any suggestions for what it could be and if it is tails shaft balancing, any recommendations in SE suburbs melbourne? Thanks!