[jadewombat]

EDIS is electronic distributor-less ignition system, I seem to remember. It's a wasted-spark system which fires twice per cycle--once on the compression stroke and once on the exhaust stroke. The exhaust stroke is considered the "wasted" spark, but it's burning the rest of the fuel that wasn't burned on the compression stroke.

In real terms, what you'll find is that the engine runs waaaay better with crank-trigger. You can run much more advance than a conventional distributor, the motor runs cooler because it's more efficient, and of course a little bump in mpg.

A mechanical distributor is really just a 2 dimensional device, with or without a MSD or Holley box added. The engine speeds up, distributor advances more. That doesn't meet the needs of what the engine needs though necessarily.

Consider 3,000 rpms. Are the demands of the engine the same at 3,000 rpms cruising down the road at top speed on the highway, as they are at 3,000 rpms launching off the line, or 3,000 rmps going up a hill? Of course not.

The "3rd" dimension of knowing where you're at on the map (by rpms) and what the engine needs (based on vacuum and MAP sensor signal) will better match the power output and the spark.