In brief...
Wind the motor over to TDC (Top dead centre), many ways to do it, but if the Harmonic Balancer hasnt slipped its the easiest way to find TDC.
Grab your dissy and match the mark on the rotor button up with the mark on the dissy, but turn it abit off, as when you fit it, it will turn one direction. You may have to fiddle around to get it to fit so the marks line up.
Once its in, wire it up, put the bracket on it loosely. Clean the timing marks up on the Harmonic Balancer, and grab your timing light. Run the engine, and turn the dissy till the timing marks on the balancer and light line up to where you want it. You only have to turn the dissy a bees dick each time. Once its timed up do the bracket up tight and hook up your vacuume advanced (time it with vacuum advanced plugged)
