ive been lookin for one as well. I think if I can get the MSD 8991 or 8992 from jegs might be okay.

here's a ferret 86 on ebay but don't know if this is the right one.



https://www.ebay.com/itm/FERRET-86-DIGITAL-TIMING-LIGHT-TACH-ADV-DWELL-VOLTS-TIMING-LIGHT-MADFE-IN-USA/282743245127?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20131231084308%26meid%3Dab290307e0e9428d9d4060183ee729e3%26pid%3D100010%26rk%3D3%26rkt%3D4%26sd%3D323389559167%26itm%3D282743245127&_trksid=p2047675.c100010.m2109


408 Stroker 533 HP 520 FT LBS...........................1970 Dart RMS AlterKation