Re: Does anyone know the diameter of a 147 exhaust?
if for some reason you are unable to assertain its diameter exactly. I would like to suggest the following cut a long strip of stiff card
(flimsy paper would do at a push, on no account use wet tissue paper-warning adult supervision should be sought if you are considering using scissors) wrap your strip around the end of the exhaust pipe and mark where the two edges of the card meet. Now lay it out flat then measure the length of the paper from the edge to the mark you made . divide it by "Pi" 3.1415 this will give you the diameter .eg bit of paper turns out to me 300 mm long divided by 3.1415 means diameter is 95.49mm. simple eh.
not as simple as just holding a ruler across the end of the exhaust but i think you have to agree that my method is far more accurate.
me, i would just wrap some shiny tin foil around the end of it.