Remove the cap but leave the HT leads on, remove the vacuum pipe and lead from the coil, undo the pinch bolt, NOTE THE ORIENTATION OF THE DIZZY and pull it out - should come without too much of a struggle but if it doesn't you can unbolt the clamp from the block and take the whole lot out. Slide the new dizzy in after lining up the shaft with the drive dog. Rotating the cam back and forward as you seat the dizzy body will help to locate the drive properly - it will only fit one way. Reconnect the electrics and vacuum, set the points gap (easier done before you fit the dizzy) and static time (it's in the book) Tighten the pinch bolt, stick on the rotor arm (yes, we've all done it.....) fit the cap and away you go.