UK Car Repair: vibration, engine mountings, engine vibrations

Question
My car is a 1934 Vauxhall ASX 14hp,  runs really smooth till it reachs around 35mph then it gets a vibration its not the prop I know that for sure, the problem is there when you rev the engine at standstill so it seems that it maybe that its at certain revs, I have renewed the rubbers in the anti-vibration pully, the engine mountings have been replaced the front ones are of a modern design,  It has very slight drag on the clutch if this is of any help,  if you could help in any way,  thanks Eric  

Answer
Hello Eric, Engine vibrations are usually the result of a bad crankshaft damper or sometimes the flywheel itsself. It was a regular problem on early engines and some designers went to great lenghts to eliminate it. On many  cars of this era they were adjustable, is the damper the spring loaded type? Often you can add weights (bolts)to various rotating components, so it becomes a trial and error procedure,  ps; I would like to see a picture of your car.