Bill,
Many years ago the vacuum retard diaphram on my 70' xke started leaking. After checking with several vendors a replacement unit could not be found.
I did have an early distributor with vacuum advance under the bench that I wanted to swap in some day and thought this would be the time to do it. The only problem was that the distributor under the bench was pretty rough. My 70 " retard" distributor was in excellent condition.
With both units on the bench I realized how similar they are. In fact they have the same casting number!
Futher inspection revaled that you can quite easily convert your "retard" distributor to an advance unit by simply using the parts from an early unit. It does require drilling one hole that the factory left out and as I recall the hole was quite easy to drill using a simple hand drill. Otherwise all the early components fit perfectly.
Just thought I would pass this along to anyone wanting to convert to a vacuum advance unit.
Keith
