Reading through the RevNNator website I found a couple of clues to the huge hp gain they tested. the largest hp gain was on a bigblock with total timing set at 32 degrees. That's six degrees retarded from normal best power advance for B/RBs, which is 38 degrees. So a faster acting switch will act like the spark is advanced two degrees, adding more advance to an engine that clearly needs it.

The E-core coil that is easiest to find was used on all TFI (Thick Film Ignition) fords. For example, my 89 Taurus had one, Mustangs of the same year. See this link:
http://www.ebay.com/itm/261647237128?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Borg-Warner Select FD478.

R.