high volt ignition coils

[FC Zach]

Originally Posted by t_g_farrell

Interesting, the Merc Marine and Jacob C4 all basically look like a
Ford TFI coil.

I'm not a 3rd gen guy but I'm using two HEI igniters (4 prong) to
drive 2 Ford TFI coils (one connected to each leading plug). No
trailing. It all works great and flawlessly. I sourced mine off of
some F150 pickups at the junkyard for $10 each. These work
up to 8K with no issues. Heres a pic of the install:

They do have similarities. The newer Jacobs coils have even changed their connector to the Ford 2 pin connector.