I know that those were what you were referring to Phil, but I could not resist theopportunity of broadening the discussion of electronic ignitions.

The J&S Safeguard unit (jandssafeguard.com) that we use is just one of several knock sensing units now available. Most aftermarket programable fuel injection/ignition systems have knock sensing capability, and I believe that MSD and Crane also have units that can be added to their ignitions.

The J&S is nice in that it is a stand alone unit, compatable with points or most standard types of points replacement ignitions such as Pertronix. It does not in itself replace the points. It is a high energy ignition, includes a rev limiter,
and is fully adustable. One version retards the timing based on knock sensing only, another includes a MAP sensor and retards based on boost as well. ( It can also be set to start retardig a 10" vacuum, so it acts like a vacuum advance.)The best part is the way it does the knock sensing and timing retard. Instead of retarding the timing of all cylinders if one is detonating, it just retards the timing in the cylinder that has the problem, keeping the other cylinder timing at the settings best for power and economy. It constantly senses the max timing for each cylinder and only retards the amount necessary to keep it from detonating, knocking, pinging. I first used this unit on a B18B, 10 - 1 compression ratio, and over 10 lbs. boost. Could not have come anywhere near that without it.
It uses either a standard Bosch or Delco knock sensor, and these are very easily
screwed into the block. We usually screw it into the block drain on the right rear of the block. Other than that installation is one hot wire, one ground, and a splice into the wire from the coil to the distributor. The standard coil is used.
I know that I am not supposed to do commercial things here, but if 3 or more members of the 1800 list, the brickboard, and/or turbobricks are interested I can offer the units at substantial discount for purchases at approximtely the same time.
Please let me know if anyone has other questions.

John
V-Performance.com