[Grady Clay]

Tom,
Great summery.


Henry,
I did the same thing in the mid ‘70s, sans oil pump. It was driven off the MFI cam. It used two machined parts and a stock rotor (rev-limit or not) and cap, less than $100. The cap was similar to the 962 one you show, screw down with a rubber gasket (not a Porsche part at the time.) It required 90 degree wire connectors to clear the stock heat exchanger or race headers.

Note the long arc of the rotor contact. Since there is no advance mechanism to keep the rotor aligned with the cap contact it is necessary to have that long arc and careful alignment to the cap. Note the long slots in the base.

Back then I used two Delta Mk 10 CDI ($50 each) designed to fire off one set of points in the original distributor (same set-up as we used on all the 4-cam Carreras.) We limited the range of the advance curve.
This also worked well with the 4-point Marelli C6 distributor where I could switch select different points for different total advance. Early DME.

With an “E” and an “S” rev-limiter rotors, it gave a great soft limit in the days before electronic limiters.

It all worked great. You have to know what to look for to tell that it is twin plug.

Best,
Grady